Fix mem leak.

Patch by Ralf Terdic contact >AT< jswiff com

Originally committed as revision 15612 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/libx264.c

@@ -124,6 +124,8 @@ X264_close(AVCodecContext *avctx)
 {
     X264Context *x4 = avctx->priv_data;
 
+    av_freep(&avctx->extradata);
+
     if(x4->enc)
         x264_encoder_close(x4->enc);