base

Leave zen when apps set ringer-mode = non-silent (normal/vibrate).

Apps can end up in priority mode by setting ringer-mode = silent.

Now they can leave priority mode by setting ringer-mode = non-silent.
  (normal or vibrate)

Bug: 17884168
Change-Id: I54c853885f4ae9ee618041dd7ac6ab0663fc7b37