Added a makeInvisible call to Face Unlock

This makes it so that the view is hidden immediately when
a call to stop is made.  This also changes the call in onPause to
only stop and not go to the backup because we still want Face Unlock
to show as the view is being dragged down.

Change-Id: I66d8fc24e82dc3a0155f7d59d8ced932cb584660