Fix SystemUI memory leaks on theme changes.

ContentObserver and BroadcastReceiver instances were dangling after the
status bar was recreated.

Change-Id: I0ef7ef134029e5deec066d405545b8d9ec58d76b
Merge remote-tracking branch 'cm/cm-10.1' into cm-10.1

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/phone/QuickSettingsController.java