Fix NPE resulting from attendees-only update from server

* Code for updating attendees in CalendarProvider2 wasn't taking
  an attendees-only update into consideration
* Fix code to allow for this, including proper updates for our
  selfAttendeeStatus and attendees ExtendedProperty values

Bug: 2668682
Change-Id: I8c7deb971cd0b6846c09ee3cd603f6fc762a9407
1 file changed