Allow three digit phone numbers

The comment for the PHONE pattern says:

"<digit><digit|sdd>+<digit>"

But the actual pattern requires that the string contains
more than that. A phone number should be allowed to be
three digits.

Change-Id: I86d2f3d634cd0c1654dad9814906f151055dc23a
Detach engines before destroying WallpaperService

WallpaperService contained a race condition where the service might be
destroyed before all its engines had been detached. For subclass
ImageWallpaper this would leak the engine's BroadcastListener, which in
turn would trigger a system crash (as ImageWallpaper runs as part of
the system).

Change-Id: Ia900173a1d3070cbf6bcf769f68376c8c8cbc62a