check for any seeking failure during probe

Originally committed as revision 8173 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/utils.c

@@ -478,7 +478,7 @@ int av_open_input_file(AVFormatContext **ic_ptr, const char *filename,
             /* read probe data */
             pd->buf= av_realloc(pd->buf, probe_size);
             pd->buf_size = get_buffer(pb, pd->buf, probe_size);
-            if (url_fseek(pb, 0, SEEK_SET) == (offset_t)AVERROR(EPIPE)) {
+            if (url_fseek(pb, 0, SEEK_SET) < 0) {
                 url_fclose(pb);
                 if (url_fopen(pb, filename, URL_RDONLY) < 0) {
                     file_opened = 0;