New Halo drawables thanks to Arz Bhatia and PA team

Change-Id: Ic63b433466d686a645133d987bfc17ba4b6ff42d

Conflicts:
	packages/SystemUI/res/drawable-hdpi/ic_notify_halo_normal.png
	packages/SystemUI/res/drawable-hdpi/ic_notify_halo_pressed.png
	packages/SystemUI/res/drawable-mdpi/ic_notify_halo_normal.png
	packages/SystemUI/res/drawable-mdpi/ic_notify_halo_pressed.png
	packages/SystemUI/res/drawable-xhdpi/ic_notify_halo_normal.png
	packages/SystemUI/res/drawable-xhdpi/ic_notify_halo_pressed.png