Removed needless dep on Microsoft.EFC.Design

Author: roji

src/Npgsql.EntityFrameworkCore.PostgreSQL.Design/Internal/NpgsqlDesignTimeServices.cs

@@ -23,7 +23,6 @@
 
 using JetBrains.Annotations;
 using Microsoft.EntityFrameworkCore.Metadata;
-using Microsoft.EntityFrameworkCore.Migrations.Design;
 using Microsoft.EntityFrameworkCore.Storage;
 using Microsoft.EntityFrameworkCore.Storage.Internal;
 using Microsoft.Extensions.DependencyInjection;

src/Npgsql.EntityFrameworkCore.PostgreSQL.Design/project.json

@@ -19,7 +19,6 @@
   },
   "dependencies" : {
     "Microsoft.EntityFrameworkCore": "1.1.0-*",
-    "Microsoft.EntityFrameworkCore.Design": "1.0.0-preview3-*",
     "Microsoft.EntityFrameworkCore.Relational": "1.1.0-*",
     "Microsoft.EntityFrameworkCore.Relational.Design": "1.1.0-*",
     "Microsoft.Extensions.DependencyInjection": "1.1.0-*",