git-submodule: remember to checkout after clone

After the initial clone of a submodule, no files would be checked out in
the submodule directory if the submodule HEAD was equal to the SHA-1
specified in the index of the containing repository. This fixes the problem
by simply ignoring submodule HEAD for a fresh clone.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-submodule.sh

@@ -100,12 +100,13 @@ modules_update()
 		if ! test -d "$path"/.git
 		then
 			module_clone "$path" "$url" || exit
+			subsha1=
+		else
+			subsha1=$(unset GIT_DIR && cd "$path" &&
+				git-rev-parse --verify HEAD) ||
+			die "Unable to find current revision of submodule '$path'"
 		fi
 
-		subsha1=$(unset GIT_DIR && cd "$path" &&
-			git-rev-parse --verify HEAD) ||
-		die "Unable to find current revision of submodule '$path'"
-
 		if test "$subsha1" != "$sha1"
 		then
 			(unset GIT_DIR && cd "$path" && git-fetch &&