shallow: add repository argument to is_repository_shallow

Add a repository argument to allow callers of is_repository_shallow
to be more specific about which repository to handle. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/upload-pack.c b/upload-pack.c
index 4e4ac0f..51b9038 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -707,7 +707,7 @@ static void send_unshallow(const struct object_array *shallows)
 static void deepen(int depth, int deepen_relative,
 		   struct object_array *shallows)
 {
-	if (depth == INFINITE_DEPTH && !is_repository_shallow()) {
+	if (depth == INFINITE_DEPTH && !is_repository_shallow(the_repository)) {
 		int i;
 
 		for (i = 0; i < shallows->nr; i++) {