Fix upload/download of attendee status

* It turns out that the UI uses selfAttendeeStatus and the attendee's status
  from the Attendees table in confusing and undocumented ways
* selfAttendeeStatus is used in the UI, but only in certain cases. Generally speaking,
  the Attendees table status is definitive.  However, when the user sets his status
  from the UI, this data is reflected in the event's selfAttendeeStatus, since for EAS,
  the user is always the owner of his calendar
* On downsync,  we'll put the user's busy status into the Attendees table
* On upsync, we'll send busy status based on the user's attendee status in the
  Attendees table
* We'll use selfAttendeeStatus only to determine whether the user has manually changed
  his status via the UI (as before)

Bug: 2615586
Change-Id: I3a82474cfd07cbf5aa595e5214807cb55005cefa
3 files changed