Removed all the unused directives in the Solution with the assistance of Resharper

src/Infrastructure/Identity/Migrations/20170822214310_InitialIdentityModel.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using Microsoft.EntityFrameworkCore.Migrations;
 using Microsoft.EntityFrameworkCore.Metadata;
 

src/Infrastructure/Identity/Migrations/AppIdentityDbContextModelSnapshot.cs

@@ -2,8 +2,6 @@
 using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Metadata;
-using Microsoft.EntityFrameworkCore.Migrations;
-using Microsoft.eShopWeb.Infrastructure.Identity;
 
 namespace Microsoft.eShopWeb.Infrastructure.Identity.Migrations
 {