Hammer CLI

Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1295780
Description of problem:
Rename the sub-command add-override-value to add-matcher under sc-param.

add-override-value tends to set the default value by overriding the parameter which was not overrided earlier. And as per discussion with Dev and behaviour of this sub-command its better to rename it to add-matcher.

Version-Release number of selected component (if applicable):
foreman-1.11.0-0.develop.201512111432git98f6ca5.el7.noarch

How reproducible:

Steps to Reproduce:
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Actual results:

Expected results:
Rename add-override-value to add-matcher under sc-param.

Additional info: