Make av_open_input_file() return AVERROR_INVALIDDATA rather than

AVERROR_NOFMT if the format is unknown / cannot be recognized.

It is returned AVERROR_INVALIDDATA, in the sense that the data is
invalid within what the specific libav* binary supports.

That was the last remaining use of AVERROR_NOFMT, which is going to be
dropped at the next libavutil major bump.

Originally committed as revision 22625 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/utils.c

@@ -560,7 +560,7 @@ int av_open_input_file(AVFormatContext **ic_ptr, const char *filename,
 
     /* if still no format found, error */
     if (!fmt) {
-        err = AVERROR_NOFMT;
+        err = AVERROR_INVALIDDATA;
         goto fail;
     }