remove all GroupAttendeeReconciliationWork items so that CalendarObject.reconcileGroupAttendees() is only called once per event instead of once per group per event
remove all GroupAttendeeReconciliationWork items so that CalendarObject.reconcileGroupAttendees() is only called once per event instead of once per group per event


git-svn-id: 0c33e958600270102f91bf5868e396345dde476c@13335 e27351fd-9f3e-4f54-a53b-843176b1656c

red-hood/calendarserver,red-hood/calendarserver,red-hood/calendarserver,red-hood/calendarserver,red-hood/calendarserver,red-hood/calendarserver