refs #5271 - prepare comps for el7 builds

also remove f19 comps files and clean out katello-cli references
Fixes #7214: add !optional to @extends, required after sass update

There were sass errors occurring on load after we upgraded sass.
This commit adds !optional to the @extends so we don't get an error.

http://projects.theforeman.org/issues/7214
Merge pull request #4600 from waldenraines/7214

Fixes #7214: add !optional to @extends, required after sass update
Merge pull request #4599 from jlsherrill/5271-comps

refs #5271 - prepare comps for el7 builds