fftools/ffmpeg_opt: Fix leak of options when parsing options fails

Fixes #8094.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 21265f42ec)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

ffmpeg_opt.c

@@ -3132,6 +3132,7 @@ static int open_files(OptionGroupList *l, const char *inout,
         if (ret < 0) {
             av_log(NULL, AV_LOG_ERROR, "Error parsing options for %s file "
                    "%s.\n", inout, g->arg);
+            uninit_options(&o);
             return ret;
         }