Fix improper constant to allow retry for sending Exchange mail

* Related to MR1 triaged bug 2274389 in which mail was stuck in the
  Outbox and wouldn't send
* It turns out an improper constant was being used in the SQL code
  for turning off the "error" state flag

Change-Id: Ic1a2e5b9dd34ec3f9d7da0b3d2cd63d77bb7681e
1 file changed