prune-packed: check for too many arguments

Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/prune-packed.c

@@ -62,6 +62,11 @@ int cmd_prune_packed(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix, prune_packed_options,
 			     prune_packed_usage, 0);
 
+	if (argc > 0)
+		usage_msg_opt(_("too many arguments"),
+			      prune_packed_usage,
+			      prune_packed_options);
+
 	prune_packed_objects(opts);
 	return 0;
 }