Fix missed case related to old CalendarProvider change

* We missed a case in which we needed to add asSyncAdapter when
  writing ExtendedProperties to CalendarProvider2
* This breaks any attempt to upload changes to attendee status
* Finding this at the last moment is Yet another indication of
  how our Exchange testing is painfully  broken
* The fix is extremely safe, and recommended for all branches

Bug: 5576733
Change-Id: Ibe28b82e329ed81f59b1a4db04e9b09ea7854198
1 file changed