EasService fixes & improvements.

- Make sure to call EmailContent.init.
- Add function to determine if an account needs to ping.
  This is currently unused but will be necessary later.
- Track the last ping/not ping status in PingSyncSynchronizer.
  This is used to know whether to restart a ping, rather than
  expecting the EasService to pass this in.

(NOTE: This CP was missed from exchange branch initially, but
some of the diffs got applied in another way.)

Change-Id: Ibb0aa45cf5174ea5dd3ba6210104a25e9060dcf8
3 files changed