* Make most calls to AccountBackupRestore return immediately w/o DB access
* Move most workers in MailService into async runnables
* Remove account restore / null check from ACTION_SEND_PENDING_EMAIL
* Strengthened unit test on Mailbox.findMailboxOfType() because after
removing the account check (above), sendPendingMessages depends on
findMailboxOfType() returning -1 on a missing account.
* Clean up a bunch of warnings (no longer use deprecated Config.LOGD)
Bug: 3133763 (and probably others)
Change-Id: Id39707bca7a8ebf5000f84d542013411ff0f422e
6ebaa90847