Don't need to check for NULL before av_free().

And don't need to memset(0) the no more used priv_data.

Originally committed as revision 6925 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/matroska.c

@@ -2609,11 +2609,8 @@ matroska_read_close (AVFormatContext *s)
     MatroskaDemuxContext *matroska = s->priv_data;
     int n = 0;
 
-    if (matroska->writing_app)
         av_free(matroska->writing_app);
-    if (matroska->muxing_app)
         av_free(matroska->muxing_app);
-    if (matroska->index)
         av_free(matroska->index);
 
     if (matroska->packets != NULL) {
@@ -2626,22 +2623,15 @@ matroska_read_close (AVFormatContext *s)
 
     for (n = 0; n < matroska->num_tracks; n++) {
         MatroskaTrack *track = matroska->tracks[n];
-        if (track->codec_id)
             av_free(track->codec_id);
-        if (track->codec_name)
             av_free(track->codec_name);
-        if (track->codec_priv)
             av_free(track->codec_priv);
-        if (track->name)
             av_free(track->name);
-        if (track->language)
             av_free(track->language);
 
         av_free(track);
     }
 
-    memset(matroska, 0, sizeof(MatroskaDemuxContext));
-
     return 0;
 }