Separate object name errors from usage errors

Separate object name errors from usage errors.

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/ssh-upload.c b/ssh-upload.c
index b675a0b..2da6661 100644
--- a/ssh-upload.c
+++ b/ssh-upload.c
@@ -134,7 +134,7 @@
 	commit_id = argv[arg];
 	url = argv[arg + 1];
 	if (get_sha1(commit_id, sha1))
-		usage(ssh_push_usage);
+		die("Not a valid object name %s", commit_id);
 	memcpy(hex, sha1_to_hex(sha1), sizeof(hex));
 	argv[arg] = hex;