remote: check for superfluous arguments in 'git remote add'

The 'git remote add' subcommand did not check for superfluous command
line arguments.  Make it so.

Signed-off-by: Thomas Rast <trast@inf.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/remote.c b/builtin/remote.c
index 937484d..5e54d36 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -178,7 +178,7 @@
 	argc = parse_options(argc, argv, NULL, options, builtin_remote_add_usage,
 			     0);
 
-	if (argc < 2)
+	if (argc != 2)
 		usage_with_options(builtin_remote_add_usage, options);
 
 	if (mirror && master)