修复未登录状态下商品只能加入一个的bug

@@ -40,11 +40,11 @@ class CartData
 		$param['selected'] = 'Y';
 		$param['promotion_id'] = $promotionId;
 
-		if ($uid !== null) {
+		if (!empty($uid)) {
 			$param['uid'] = $uid;
 		}
 		if ($shoppingKey !== null) {
-			$param['shoppingKey'] = $shoppingKey;
+			$param['shopping_key'] = $shoppingKey;
 		}
 		$param['client_secret'] = Sign::getSign($param);