options: return EXIT_SUCCESS after displaying help message

`getopt_long` already supplies a message when an option cannot be parsed,
so there isn't a need to distinguish option parse failures from help
requests.

Fixes: https://github.com/Zygo/bees/pull/277
Signed-off-by: Zygo Blaxell <bees@furryterror.org>

src/bees.cc

@@ -814,7 +814,7 @@ bees_main(int argc, char *argv[])
 			case 'h':
 			default:
 				do_cmd_help(argv);
-				return EXIT_FAILURE;
+				return EXIT_SUCCESS;
 		}
 	}