Update ASP.NET 5 versions for ASP.NET Core.
Update ASP.NET 5 versions for ASP.NET Core.

See https://github.com/aspnet/Announcements/issues/144 for more information.

aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore