fix session reset

@@ -25,7 +25,7 @@ const index = (req, res, next) => {
     });
 
     // 清除 session
-    req.session = {};
+    req.session.reset();
 
     service.indexPageDataAsync()
         .then(result => {

@@ -117,7 +117,7 @@ const local = {
             domain: config.cookieDomain
         });
 
-        req.session = {};
+        req.session.reset();
 
         let bindMobile = _.trim(req.query.bindMobile || '');
         let bindArea = '+' + _.trim(req.query.bindArea || '86');