lavf: dont open a decoder at the top of find_stream_info before probing has finished

It could open the wrong decoder.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/utils.c

@@ -2557,7 +2557,7 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
                               : &thread_opt);
 
         //try to just open decoders, in case this is enough to get parameters
-        if (!has_codec_parameters(st, NULL)) {
+        if (!has_codec_parameters(st, NULL) && st->request_probe <= 0) {
             if (codec && !st->codec->codec)
                 avcodec_open2(st->codec, codec, options ? &options[i]
                               : &thread_opt);