Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1376924

Description of problem:
provisioning a client with 2 nics will have to default gateways.

Version-Release number of selected component (if applicable):

Foreman 1.11+

How reproducible:

Create 2 subnets and specify the gateway for etch one then create a client and add 2 networks to point to these 2 subnets. After you kickstart the client the client will have 2 default gateways. when we create a new host we need to have an option to specify the default gateway instead to remove the gateway from the subnets.