Merge branch 'me/fetch-into-shallow-safety' into maint

"git fetch --depth=<depth>" and "git clone --depth=<depth>" issued
a shallow transfer request even to an upload-pack that does not
support the capability.

* me/fetch-into-shallow-safety:
  fetch-pack: check for shallow if depth given

fetch-pack.c

@@ -790,7 +790,7 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 	sort_ref_list(&ref, ref_compare_name);
 	qsort(sought, nr_sought, sizeof(*sought), cmp_ref_by_name);
 
-	if (is_repository_shallow() && !server_supports("shallow"))
+	if ((args->depth > 0 || is_repository_shallow()) && !server_supports("shallow"))
 		die("Server does not support shallow clients");
 	if (server_supports("multi_ack_detailed")) {
 		if (args->verbose)