ffmpeg_opt: Fix -target vcd

The removed line makes no sense and doesnt work

fixes ticket #3239
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

ffmpeg_opt.c

@@ -2133,7 +2133,6 @@ static int opt_target(void *optctx, const char *opt, const char *arg)
         opt_video_codec(o, "c:v", "mpeg1video");
         opt_audio_codec(o, "c:a", "mp2");
         parse_option(o, "f", "vcd", options);
-        av_dict_set(&o->g->codec_opts, "b:v", arg, AV_DICT_DONT_OVERWRITE);
 
         parse_option(o, "s", norm == PAL ? "352x288" : "352x240", options);
         parse_option(o, "r", frame_rates[norm], options);