The read_packet callback passes a pointer to a stack-allocated AVPacket.
Attempting to free it with av_free() makes no sense.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit b173f5c1)

Conflicts:

	libavformat/oggdec.c
(cherry picked from commit a82401b7284e05e2cf6fb89aeed53738af06a7fd)
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>