cherrypick:Fix longstanding EAS battery burner

* This happens when the plain text of an Exchange 2003 message
  is more than about 500k characters; what's happening is that
  a TransactionTooLarge exception is being thrown in the binder
* The reason we never figured it out previously is that the
  exception isn't listed in emaillog.txt (which users can easily
  send); bugreports/logcat output is harder...
* The fix is to progressively truncate the text

fixes b/7232917 Looping sync (Exchange 2003, retrieving HTML mail body)
Change-Id: I7524070721e7c25b490200293cb8efb8dfd99d05
1 file changed