Reduce translations by using same terminologies

Somewhere in help usage, we use both "message" and "msg", "command"
and "cmd", "key id" and "key-id". This patch makes all help text from
parseopt use the first form. Clearer and 3 fewer strings for
translators.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/archive.c b/archive.c
index 2584324..4666404 100644
--- a/archive.c
+++ b/archive.c
@@ -343,7 +343,7 @@
 		OPT_GROUP(""),
 		OPT_STRING(0, "remote", &remote, N_("repo"),
 			N_("retrieve the archive from remote repository <repo>")),
-		OPT_STRING(0, "exec", &exec, N_("cmd"),
+		OPT_STRING(0, "exec", &exec, N_("command"),
 			N_("path to the remote git-upload-archive command")),
 		OPT_END()
 	};