Ignore x264 build=0 as there is no such version, this restores previous

behavior approximately.

Originally committed as revision 22628 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h264_sei.c

@@ -109,7 +109,7 @@ static int decode_unregistered_user_data(H264Context *h, int size){
 
     user_data[i]= 0;
     e= sscanf(user_data+16, "x264 - core %d"/*%s - H.264/MPEG-4 AVC codec - Copyleft 2005 - http://www.videolan.org/x264.html*/, &build);
-    if(e==1 && build>=0)
+    if(e==1 && build>0)
         h->x264_build= build;
 
     if(s->avctx->debug & FF_DEBUG_BUGS)