Fix derp observer

If per app color is disabled, pie gravity ain't work?

Change-Id: Ia1c1cfc23b521863db7993cad2581b38ea011f0a

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/BaseStatusBar.java
Derp

Change-Id: I930a774071b450b4d4668712054a6c36d3bb579d