avformat/avidec: Use av_freep() to avoid leaving stale pointers in memory

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/assenc: Use av_freep() to avoid leaving stale pointers in memory

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/xmv: use av_freep() to avoid leaving stale extradata pointer

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/rtpdec_mpeg4: Use av_freep() to avoid leaving stale extradata pointer

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/flic: se av_freep() to avoid leaving stale extradata pointer

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avformat/xmv: Check return code of ff_alloc_extradata()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>