Suspend LocalMediaServer when all WebkitCameraSrc is changed to null state.
[Title] Suspend LocalMediaServer when all WebkitCameraSrc is changed to null state.
[Issue#] https://tizendev.org/bugs/browse/N_SE-33840
[Problem] After running 'SelfCamera', can't run other camera apps properly.
[Cause] LocalMedaiServer don't release camera device when the app goes to background.
[Solution] Suspend LocalMediaServer when all WebkitCameraSrc is changed to null state.
Change-Id: I7550960de7c07bf762f98734af14773f06ce8a5c