revert r12809

Log:
	10l
	Setting AVFMTCTX_NOHEADER if streams<2 so phantom streams are found.
	fixes WELCOMETOBELGRADE.flv
As it unexpectly breaks seek regression tests.

Originally committed as revision 12811 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/flvdec.c

@@ -256,9 +256,6 @@ static int flv_read_header(AVFormatContext *s,
         flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
         av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
     }
-    if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
-             != (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
-        s->ctx_flags |= AVFMTCTX_NOHEADER;
 
     if(flags & FLV_HEADER_FLAG_HASVIDEO){
         if(!create_stream(s, 0))