lavf: free probe data in case we close before probing finished

Fixes Ticket1634
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/utils.c

@@ -3056,6 +3056,7 @@ void ff_free_stream(AVFormatContext *s, AVStream *st){
     av_freep(&st->codec);
     av_freep(&st->priv_data);
     av_freep(&st->info);
+    av_freep(&st->probe_data.buf);
     av_freep(&s->streams[ --s->nb_streams ]);
 }