SystemUI: Avoid NPEs during status bar recreation for MSIM

PS2:
   * Clear the subs views on recreation
   * Unregister receivers on recreation

Change-Id: Id131ffac497f46a753a97b479823e51fda7c412c
Signed-off-by: anerikg <anerikgames@gmail.com>

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