Only handle mailbox alarms for EAS mailboxes

* Fixes #2135238 in which a change to a POP/IMAP mailbox
  ended up causing a sync of that box as an EAS mailbox
* The fix is to check that mailboxes with changes actually
  belong to an EAS account before trying to sync them

Change-Id: I832095ce61665813cbcfb2aa58e45a48db8a34e7
2 files changed