Use av_freep() in ff_parse_close().

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@15654 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/parser.c

@@ -291,7 +291,7 @@ void ff_parse_close(AVCodecParserContext *s)
 {
     ParseContext *pc = s->priv_data;
 
-    av_free(pc->buffer);
+    av_freep(&pc->buffer);
 }
 
 void ff_parse1_close(AVCodecParserContext *s)