Change free_sh_audio() to take demuxer and stream id as parameters
(same as new_sh_audio()) instead of sh_audio_t *, use those to remove
the pointer from demuxer->a_streams[] before freeing it.
Some demuxers use free_sh_audio() to undo the creation of an
already-allocated audio stream in case of error. These uses were unsafe
since free_sh_audio() freed the data structure but left the pointer in
demuxer->a_streams[], leading to double free later in free_demuxer()
(and perhaps use of the freed stream before that, I didn't check).
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@18711 b3059339-0415-0410-9bf9-f77b7e298cf2