edit app-backend msg db to 4.3

nodejs/app-backend.js

@@ -34,7 +34,7 @@ module.exports = {
   		database: 'mall'
   	},
     msgDb: {
-        host: db,
+        host: "192.168.4.3",
         user: 'qa',
         password: 'qatest',
         database: 'msg'