Fixes #6039 - CP events in CH tasks tab

This fix displays the candlepin events by placing them as sub tab under
the content-host subscriptions tab.
fixes #6963 - make templates compatible with RHEL 5
Merge pull request #4536 from stbenjam/6963

fixes #6963 - make templates compatible with RHEL 5
Merge pull request #4425 from dustint-rh/ch_events

Fixes #6039 - CP events in CH tasks tab