Fix double free which happens for playback of .rm files after r16365. See

"rmdec.c: double free" discussion on mailinglist, patch with suggestions
from Reimar Doffinger.

Originally committed as revision 16378 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rdt.c

@@ -438,6 +438,7 @@ static void
 rdt_free_extradata (PayloadContext *rdt)
 {
     ff_rm_free_rmstream(rdt->rmst[0]);
+    av_free(rdt->rmst[0]);
     if (rdt->rmctx)
         av_close_input_stream(rdt->rmctx);
     av_freep(&rdt->mlti_data);

libavformat/rmdec.c

@@ -83,7 +83,6 @@ void ff_rm_free_rmstream (RMStream *rms)
 {
     av_free(rms->videobuf);
     av_free(rms->audiobuf);
-    av_free(rms);
 }
 
 static int rm_read_audio_stream_info(AVFormatContext *s, ByteIOContext *pb,