Since bae8844e the packet will always be unreferenced when a demuxer
returns an error, so that a lot of calls to av_packet_unref() in lots of
demuxers are now redundant and can be removed.
Signed-off-by: NAndreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: NMarton Balint <cus@passwd.hu>