smart-http: support shallow fetch/clone

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

upload-pack.c

@@ -836,8 +836,6 @@ int main(int argc, char **argv)
 
 	if (!enter_repo(dir, strict))
 		die("'%s' does not appear to be a git repository", dir);
-	if (is_repository_shallow() && stateless_rpc)
-		die("attempt to push into a shallow repository");
 
 	git_config(upload_pack_config, NULL);
 	upload_pack();