msdkdec: fix surface leak in msdkdec_handle_frame
Can be reproduced with:
videotestsrc ! x264enc key-int-max=$N !
h264parse ! msdkh264dec ! fakesink sync=1
It happens with any gop size but the smaller is the distance N between key frames, the quicker it is leaking.
Fixes #1023 (closed)
Edited by Julien Isorce