Update list on ACTION_DEVICE_POLICY_MANAGER_STATE_CHANGED

Added BroadcastReceiver for ACTION_DEVICE_POLICY_MANAGER_STATE_CHANGED to
refresh the list, if event has been received. It could be that checkboxes
need to be updated. Also disable the checkbox while admin is being removed.

Bug: 17609838
Change-Id: Id1f72c27111c280a77a03ba6ba26bcdbbb10bb58