Add a ff_h264_free_context function and call it from the H.264 parser.

This ensures that the parser will no longer leak memory for all SPS/PPS it encounters.

Originally committed as revision 18406 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h264_parser.c

@@ -306,6 +306,7 @@ static void close(AVCodecParserContext *s)
     ParseContext *pc = &h->s.parse_context;
 
     av_free(pc->buffer);
+    ff_h264_free_context(h);
 }