Fix git-commit without paths.

The earlier one to grab output from diff-files --name-only has a grave
bug that when no paths are given it ended up doing the equivalent of
"git-commit --all", which was not what I intended.

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

git-commit-script

@@ -85,11 +85,13 @@ tt*)
   die "Only one of -c/-C/-F/-m can be used." ;;
 esac
 
-case "$all" in
-t)
+case "$all,$#" in
+t,*)
 	git-diff-files --name-only -z |
 	xargs -0 git-update-cache -q --
 	;;
+,0)
+	;;
 *)
 	git-diff-files --name-only -z "$@" |
 	xargs -0 git-update-cache -q --