Exit Emergency callback mode if modem resets

If the modem resets when the phone is in Emergency
callback mode, exit emergency callback mode.

Bug: 62255356
Test: New unit test "testModemResetInEmergencyCallbackMessages"
      in GsmPhoneTest under telephonytests
Change-Id: I3030b59292252e4c0a6c91603f52084cee59d885