efcore: Migrations Design: Invalid 'using' statements for default namespace

Invalid using ; added to generated migration file because this simple project has no default namespace.

Setup https://gist.github.com/natemcmaster/90e2388c0ee1d29f440a.

Using dnx 1.0.0-beta6-12114 , EF 7.0.0-beta6-13584

dnx . ef migration add Initial

produces 20150624223653_Initial.Designer.cs which includes this at the top of the file:

using System;
using Microsoft.Data.Entity;
using Microsoft.Data.Entity.Metadata;
using Microsoft.Data.Entity.Relational.Migrations.Infrastructure;
using ;

The same using block appears in ModelSnapshot.cs