Update comment about GStreamer pipeline
Update comment about GStreamer pipeline

autovideosink doesn't work in some environments, replacing
it with ximagesink.

smartdevicelink/sdl_ios,FordDev/sdl_ios,APCVSRepo/sdl_ios,FordDev/sdl_ios,APCVSRepo/sdl_ios,smartdevicelink/sdl_ios,smartdevicelink/sdl_ios,kshala-ford/sdl_ios,FordDev/sdl_ios,kshala-ford/sdl_ios,smartdevicelink/sdl_ios,smartdevicelink/sdl_ios,APCVSRepo/sdl_ios,APCVSRepo/sdl_ios,kshala-ford/sdl_ios,APCVSRepo/sdl_ios,FordDev/sdl_ios,kshala-ford/sdl_ios,FordDev/sdl_ios,kshala-ford/sdl_ios