Fixes #5944: Ensure links to old Katello pages are followed.

After switching to HTML5 history, links to older Katello pages that
included hashes would not properly redirect. This now checks if the path
starts with '/katello' and force redirects to the specified url.
Merge pull request #4318 from ehelms/fixes-5944

Fixes #5944: Ensure links to old Katello pages are followed.