git-remote: no longer silent on unknown commands.

Signed-off-by: NQuy Tonthat <qtonthat@gmail.com>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

git-remote.perl

@@ -274,4 +274,9 @@ sub add_remote {
 	}
 	add_remote($ARGV[1], $ARGV[2]);
 }
-
+else {
+	print STDERR "Usage: git remote\n";
+	print STDERR "       git remote add <name> <url>\n";
+	print STDERR "       git remote show <name>\n";
+	exit(1);
+}