fix bug

app-hd/controllers/MtController.php

@@ -56,7 +56,7 @@ class MtController extends PublicController
             $params = ['app_poi_code' => $data['appPoiCode'], 'app_spu_code' => $appSpuCode];
             $retailDetail = $app->retail->getDetail($params);
             $retailDetail = json_decode($retailDetail, true);
-            if (is_set($retailDetail['error'])) {
+            if (isset($retailDetail['error'])) {
                  Yii::error('get retail fail:' . json_encode($params));
             } else {
                 $picArr[$appSpuCode] = $retailDetail['data']['picture'];