Working in VS2015 on a web project based on ASP.NET Core (former ASP.NET 5), .NET Core CLR RC1, EF Core (former EF 7), EF Migrations enabled, LocalDb v11.0.
I manual
I found an easier way around
run your app and create the DB in the default location
Open Microsoft Sql Server Management Studio (or you prefer IDE) and create a new connection to point to (localdb)\mssqllocaldb
Script Database as CREATE
Change the path in the FILENAME
Remove the DB you created on step 1 (choose close existing connections)
Run the script
Your application should work without changing anything in the config