clean up installation


git-svn-id: https://svn.calendarserver.org/repository/calendarserver@13340 e27351fd-9f3e-4f54-a53b-843176b1656c
Fix multi-group group attendees. Mostly fix group attendees when group disappears from directory. Fix tests.


git-svn-id: https://svn.calendarserver.org/repository/calendarserver@13341 e27351fd-9f3e-4f54-a53b-843176b1656c