code review by fei.hong: do add criteo analysis codes

@@ -199,7 +199,7 @@ class CartModel
         $result['ids'] = empty($analysisData['ids']) ? '' : implode(',', $analysisData['ids']);
         $result['ipinyou'] = empty($analysisData['ipinyou']) ? '' : $analysisData['ipinyou'];
         $result['ipinyouAmount'] = isset($result['productAllA']) ? $result['productAllA'] : '0.00';
-        $result['criteo'] = empty($analysisData['criteo']) ? '' : json_encode($analysisData['criteo']);
+        $result['criteo'] = empty($analysisData['criteo']) ? "''" : json_encode($analysisData['criteo']);
 
         return $result;
     }