Active Display: send unlock broadcast

[log]

This will unregister the receiver and fix the memory leak.

Change-Id: Ib99c27c6ad57eaf14d7e9f1adf2a651133ed2503
Signed-off-by: Dirk Rettschlag <dirk.rettschlag@gmail.com>

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/policy/activedisplay/ActiveDisplayView.java