cleans unused refs

Yavsc/Migrations/20160905095708_tags.Designer.cs

@@ -1,7 +1,6 @@
 using System;
 using Microsoft.Data.Entity;
 using Microsoft.Data.Entity.Infrastructure;
-using Microsoft.Data.Entity.Metadata;
 using Microsoft.Data.Entity.Migrations;
 using Yavsc.Models;
 

Yavsc/Migrations/20160905095708_tags.cs

@@ -1,5 +1,3 @@
-using System;
-using System.Collections.Generic;
 using Microsoft.Data.Entity.Migrations;
 
 namespace Yavsc.Migrations