Don't show subtitle and grab options within the ffmpeg -h generic options.

Originally committed as revision 13778 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffmpeg.c

@@ -3400,7 +3400,7 @@ static void show_help(void)
            "Hyper fast Audio and Video encoder\n");
     printf("\n");
     show_help_options(options, "Main options:\n",
-                      OPT_EXPERT | OPT_AUDIO | OPT_VIDEO, 0);
+                      OPT_EXPERT | OPT_AUDIO | OPT_VIDEO | OPT_SUBTITLE | OPT_GRAB, 0);
     show_help_options(options, "\nVideo options:\n",
                       OPT_EXPERT | OPT_AUDIO | OPT_VIDEO | OPT_GRAB,
                       OPT_VIDEO);