oggdec: Metadata is per-stream; don't merge multiple streams' together

Originally committed as revision 22473 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/flacdec.c

@@ -113,7 +113,7 @@ static int flac_read_header(AVFormatContext *s,
             }
             /* process supported blocks other than STREAMINFO */
             if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
-                if (ff_vorbis_comment(s, buffer, metadata_size)) {
+                if (ff_vorbis_comment(s, &s->metadata, buffer, metadata_size)) {
                     av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");
                 }
             }