PIE: fix stuck pixel on screen redraw

Reverts: PWM: disable HW overlays for PIE de1cb4e
Uses a dummmy view to force the screen to be redrawn on screen update

Change-Id: Ia12e596f81583a3b6be1bef64ae9d46b32d410d2

Conflicts:
	policy/src/com/android/internal/policy/impl/PhoneWindowManager.java