clone-pack: remove unused and undocumented --keep flag

While we are at it, give fully spelled --keep to fetch-pack.
Also give --quiet in addition to -q to fetch-pack as well.

Signed-off-by: Junio C Hamano <junkio@cox.net>

clone-pack.c

@@ -160,8 +160,6 @@ int main(int argc, char **argv)
 				exec = arg + 7;
 				continue;
 			}
-			if (!strcmp("--keep", arg))
-				continue;
 			usage(clone_pack_usage);
 		}
 		dest = arg;