屏蔽直接访问银联支付回调页面会出现报错的bug

Code Review By Rock Zhang

@@ -40,7 +40,7 @@ class Service extends PayAbstract
         $verify = false;
         $responseData = new Rspparams();
 
-        if ($package['respCode'] !== '00') {
+        if (!isset($package['respCode']) || $package['respCode'] !== '00') {
             $this->log->LogInfo('支付返回码有误');
             $responseData->payResult = -1;
             return $responseData;