Fix issue #5108980 Wallpaper is not restored after upgrade from IRK32B to IRK33B

Take care of updating from old component name, and don't let this happen
again.

Also tweak how we switch between static wallpapers to avoid introducing
a 4MB allocation in the system UI process when this happens -- we now
stop the current wallpaper service and start a new one, so we get a
brand new surface that we can draw only one time in to.

Change-Id: I6fc8a42b8a46bba79759bd68fb7d0684b5d897b7