katello 2.0 installed via katello-deploy/setup.rb on centos 6.5/x86_64 with selinux=enforcing

To reproduce:

1.) have some stale dns-entry for example test.domain.tld
2.) add libvirt-guest via "New Host", have autosuggest an old IP with existing PTR/A-Entry
3.) Foreman asks whether this should be overwritten -> yes
4.) Foreman fails to add host because of missing MAC:

Completed 200 OK in 337ms (Views: 313.4ms | ActiveRecord: 11.3ms)
Processing by HostsController#process_hostgroup as */*
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"2OmTeOlaL4PKPMqZJt1qFJOLtW5t2tt2oervCQfkBYQ=", "host"=>{"name"=>"test", "organization_id"=>"5", "location_id"=>"3", "hostgroup_id"=>"1", "compute_resource_id"=>"", "environment_id"=>"", "content_source_id"=>"", "puppet_ca_proxy_id"=>"", "puppet_proxy_id"=>"", "managed"=>"true", "progress_report_id"=>"[FILTERED]", "type"=>"Host::Managed", "domain_id"=>"", "realm_id"=>"", "mac"=>"", "ip"=>"", "interfaces_attributes"=>{"new_interfaces"=>{"_destroy"=>"false", "type"=>"Nic::Managed", "mac"=>"", "name"=>"", "domain_id"=>"", "ip"=>"", "provider"=>"IPMI"}}, "architecture_id"=>"", "provision_method"=>"build", "build"=>"1", "disk"=>"", "root_pass"=>"[FILTERED]", "is_owned_by"=>"3-Users", "enabled"=>"1", "model_id"=>"", "comment"=>"", "overwrite"=>"false"}, "kt_environment_id"=>""}
  Rendered hosts/_progress.html.erb (0.1ms)
  Rendered puppetclasses/_selectedClasses.html.erb (0.0ms)
  Rendered puppetclasses/_classes_in_groups.html.erb (0.0ms)
  Rendered puppetclasses/_classes.html.erb (0.1ms)
  Rendered puppetclasses/_class_selection.html.erb (43.7ms)
  Rendered common/_domain.html.erb (10.7ms)
  Rendered hosts/_interfaces.html.erb (12.9ms)
  Rendered common/os_selection/_architecture.html.erb (6.5ms)
  Rendered common/os_selection/_operatingsystem.html.erb (14.8ms)
  Rendered hosts/_operating_system.html.erb (27.9ms)
  Rendered hosts/_unattended.html.erb (180.1ms)
  Rendered puppetclasses/_class_parameters.html.erb (0.0ms)
  Rendered puppetclasses/_classes_parameters.html.erb (6.7ms)
  Rendered common_parameters/_inherited_parameters.html.erb (144.6ms)
  Rendered common_parameters/_puppetclass_parameter.html.erb (2.0ms)
  Rendered common_parameters/_puppetclasses_parameters.html.erb (3.5ms)
  Rendered common_parameters/_parameter.html.erb (1.1ms)
  Rendered common_parameters/_parameters.html.erb (3.0ms)
  Rendered hosts/_form.html.erb (446.8ms)
Completed 200 OK in 472ms (Views: 434.0ms | ActiveRecord: 17.2ms)
Processing by SubnetsController#freeip as */*
  Parameters: {"subnet_id"=>"1", "host_mac"=>"", "organization_id"=>"5", "location_id"=>"3"}
Processing by HostsController#compute_resource_selected as */*
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"2OmTeOlaL4PKPMqZJt1qFJOLtW5t2tt2oervCQfkBYQ=", "host"=>{"name"=>"test", "organization_id"=>"5", "location_id"=>"3", "hostgroup_id"=>"1", "compute_resource_id"=>"1", "environment_id"=>"1", "content_source_id"=>"1", "puppet_ca_proxy_id"=>"1", "puppet_proxy_id"=>"1", "puppetclass_ids"=>[""], "managed"=>"true", "progress_report_id"=>"[FILTERED]", "type"=>"Host::Managed", "domain_id"=>"1", "realm_id"=>"", "mac"=>"", "subnet_id"=>"1", "ip"=>"", "interfaces_attributes"=>{"new_interfaces"=>{"_destroy"=>"false", "type"=>"Nic::Managed", "mac"=>"", "name"=>"", "domain_id"=>"", "ip"=>"", "provider"=>"IPMI"}}, "architecture_id"=>"1", "operatingsystem_id"=>"29", "provision_method"=>"build", "build"=>"1", "ptable_id"=>"7", "disk"=>"", "root_pass"=>"[FILTERED]", "is_owned_by"=>"3-Users", "enabled"=>"1", "model_id"=>"", "comment"=>"", "overwrite"=>"false"}, "kt_environment_id"=>""}
Completed 200 OK in 2052ms (Views: 0.7ms | ActiveRecord: 2.5ms)
  Rendered compute_resources_vms/form/libvirt/_network.html.erb (260.1ms)
  Rendered compute_resources_vms/form/libvirt/_network.html.erb (125.2ms)
  Rendered compute_resources_vms/form/libvirt/_volume.html.erb (45.3ms)
  Rendered compute_resources_vms/form/libvirt/_volume.html.erb (38.2ms)
  Rendered compute_resources_vms/form/_libvirt.html.erb (570.0ms)
  Rendered hosts/_compute.html.erb (1498.1ms)
Completed 200 OK in 1518ms (Views: 1498.7ms | ActiveRecord: 3.9ms)
Processing by ImagesController#index as JSON
  Parameters: {"search"=>"operatingsystem=29 architecture=1", "compute_resource_id"=>"1"}
Completed 200 OK in 14ms (Views: 1.2ms | ActiveRecord: 2.1ms)
Processing by HostsController#create as */*
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"2OmTeOlaL4PKPMqZJt1qFJOLtW5t2tt2oervCQfkBYQ=", "host"=>{"name"=>"test", "organization_id"=>"5", "location_id"=>"3", "hostgroup_id"=>"1", "compute_resource_id"=>"1", "environment_id"=>"1", "content_source_id"=>"1", "puppet_ca_proxy_id"=>"1", "puppet_proxy_id"=>"1", "puppetclass_ids"=>[""], "managed"=>"true", "progress_report_id"=>"[FILTERED]", "type"=>"Host::Managed", "compute_attributes"=>{"cpus"=>"1", "memory"=>"805306368", "nics_attributes"=>{"new_nics"=>{"type"=>"bridge", "_delete"=>"", "bridge"=>"bond0", "model"=>"virtio"}, "0"=>{"type"=>"bridge", "_delete"=>"", "bridge"=>"br-lab", "model"=>"virtio"}}, "volumes_attributes"=>{"new_volumes"=>{"pool_name"=>"lvm_storage", "capacity"=>"10G", "allocation"=>"0G", "format_type"=>"raw", "_delete"=>""}, "0"=>{"pool_name"=>"lvm_storage", "capacity"=>"10G", "allocation"=>"10G", "format_type"=>"raw", "_delete"=>""}}, "start"=>"1"}, "domain_id"=>"1", "realm_id"=>"", "mac"=>"", "subnet_id"=>"1", "ip"=>"192.168.0.24", "interfaces_attributes"=>{"new_interfaces"=>{"_destroy"=>"false", "type"=>"Nic::Managed", "mac"=>"", "name"=>"", "domain_id"=>"", "ip"=>"", "provider"=>"IPMI"}}, "architecture_id"=>"1", "operatingsystem_id"=>"29", "provision_method"=>"build", "build"=>"1", "ptable_id"=>"7", "disk"=>"", "root_pass"=>"[FILTERED]", "is_owned_by"=>"3-Users", "enabled"=>"1", "model_id"=>"", "comment"=>"", "overwrite"=>"false"}, "kt_environment_id"=>"", "capabilities"=>"build image", "provider"=>"Libvirt"}
DNS PTR Records 192.168.0.24/test3.domain.tld.domain.tld already exists
Failed to save: Conflict DNS PTR Records 192.168.0.24/test3.domain.tld.domain.tld already exists
  Rendered hosts/_conflicts.html.erb (0.7ms)
  Rendered hosts/_progress.html.erb (0.1ms)
  Rendered puppetclasses/_selectedClasses.html.erb (0.0ms)
  Rendered puppetclasses/_classes_in_groups.html.erb (0.0ms)
  Rendered puppetclasses/_classes.html.erb (0.5ms)
  Rendered puppetclasses/_class_selection.html.erb (44.2ms)
  Rendered compute_resources_vms/form/libvirt/_network.html.erb (127.8ms)
  Rendered compute_resources_vms/form/libvirt/_network.html.erb (138.0ms)
  Rendered compute_resources_vms/form/libvirt/_volume.html.erb (158.6ms)
  Rendered compute_resources_vms/form/libvirt/_volume.html.erb (27.4ms)
  Rendered compute_resources_vms/form/_libvirt.html.erb (547.7ms)
  Rendered hosts/_compute.html.erb (605.1ms)
  Rendered common/_domain.html.erb (10.2ms)
  Rendered hosts/_interfaces.html.erb (12.4ms)
  Rendered common/os_selection/_architecture.html.erb (123.2ms)
  Rendered common/os_selection/_operatingsystem.html.erb (15.3ms)
  Rendered hosts/_operating_system.html.erb (145.3ms)
  Rendered hosts/_unattended.html.erb (784.7ms)
  Rendered puppetclasses/_class_parameters.html.erb (0.0ms)
  Rendered puppetclasses/_classes_parameters.html.erb (6.8ms)
  Rendered common_parameters/_inherited_parameters.html.erb (6.9ms)
  Rendered common_parameters/_puppetclass_parameter.html.erb (1.4ms)
  Rendered common_parameters/_puppetclasses_parameters.html.erb (2.3ms)
  Rendered common_parameters/_parameter.html.erb (0.9ms)
  Rendered common_parameters/_parameters.html.erb (2.3ms)
  Rendered hosts/_form.html.erb (1024.3ms)
  Rendered hosts/new.html.erb within layouts/application (1025.0ms)
  Rendered home/_user_dropdown.html.erb (1.0ms)
Read fragment views/tabs_and_title_records-3 (0.1ms)
  Rendered home/_topbar.html.erb (1.6ms)
  Rendered layouts/base.html.erb (2.4ms)
Completed 200 OK in 1386ms (Views: 1016.3ms | ActiveRecord: 25.0ms)
Processing by TasksController#show as */*
  Parameters: {"id"=>"8f6325d4-0c71-49af-af5c-8d7a3625a8ea"}
  Rendered tasks/_list.html.erb (0.0ms)
Completed 200 OK in 5ms (Views: 0.6ms | ActiveRecord: 0.7ms)
Processing by HostsController#create as */*
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"2OmTeOlaL4PKPMqZJt1qFJOLtW5t2tt2oervCQfkBYQ=", "host"=>{"name"=>"test", "organization_id"=>"5", "location_id"=>"3", "hostgroup_id"=>"1", "compute_resource_id"=>"1", "environment_id"=>"1", "content_source_id"=>"1", "puppet_ca_proxy_id"=>"1", "puppet_proxy_id"=>"1", "puppetclass_ids"=>[""], "managed"=>"true", "progress_report_id"=>"[FILTERED]", "type"=>"Host::Managed", "compute_attributes"=>{"cpus"=>"1", "memory"=>"805306368", "nics_attributes"=>{"new_nics"=>{"type"=>"bridge", "_delete"=>"", "bridge"=>"bond0", "model"=>"virtio"}, "0"=>{"type"=>"bridge", "_delete"=>"", "bridge"=>"br-lab", "model"=>"virtio"}}, "volumes_attributes"=>{"new_volumes"=>{"pool_name"=>"lvm_storage", "capacity"=>"10G", "allocation"=>"0G", "format_type"=>"raw", "_delete"=>""}, "0"=>{"pool_name"=>"lvm_storage", "capacity"=>"10G", "allocation"=>"10G", "format_type"=>"raw", "_delete"=>""}}, "start"=>"1"}, "domain_id"=>"1", "realm_id"=>"", "mac"=>"", "subnet_id"=>"1", "ip"=>"192.168.0.24", "interfaces_attributes"=>{"new_interfaces"=>{"_destroy"=>"false", "type"=>"Nic::Managed", "mac"=>"", "name"=>"", "domain_id"=>"", "ip"=>"", "provider"=>"IPMI"}}, "architecture_id"=>"1", "operatingsystem_id"=>"29", "provision_method"=>"build", "build"=>"1", "ptable_id"=>"7", "disk"=>"", "root_pass"=>"[FILTERED]", "is_owned_by"=>"3-Users", "enabled"=>"1", "comment"=>"", "overwrite"=>"true"}, "kt_environment_id"=>"", "capabilities"=>"build image", "provider"=>"Libvirt"}
Operation FAILED: Invalid MAC 
  Rendered common/500.html.erb (3.7ms)
Completed 500 Internal Server Error in 101ms (Views: 5.6ms | ActiveRecord: 4.2ms)