Bug 1396957 - Synchronize CC list on security bugs over to revisions as subscribers...

Bug 1396957 - Synchronize CC list on security bugs over to revisions as subscribers (#230)

* Bug 1396957 - Synchronize CC list on security bugs over to revisions as subscribers

* - Updated to only make subscriber changes if no groups have changed.
- This cuts down on the amount of custom policy changes in the revision
activity.

* Bug 1396957 - Synchronize CC list on security bugs over to revisions as subscribers

* - Updated to only make subscriber changes if no groups have changed.
- This cuts down on the amount of custom policy changes in the revision
activity.

* Bug 1396042 - Implement logging for the BMO push connector

* Bug 1397747 - Move _get_all_group_names to Bugzilla::Config::Common::_get_all_group_names, and remove copy-pasted code