Fixes #7903 - Remove call to undefined class
Fixes #7679: add the errata list page and menu item.
Merge pull request #4735 from daviddavis/temp/20141010154932

Fixes #7903 - Remove call to undefined class
Merge pull request #4730 from waldenraines/errata-list

Fixes #7679: adding errata list page.
Fixes #7685: add errata details page.

Add an errata details page that contains the same information as is
available on the RH customer portal.

http://projects.theforeman.org/issues/7685