fixed callback error handling

I recieved a `Error: Not Found at Layer.handle.......( a lot of stuff )` when i tried to invoke a 404 error page on MVC configuration.

the callback parameter on basic configuration is there, and MVC-Coffee configuration was added on this commit https://github.com/petecoop/generator-express/commit/172af2478d9bcb6d86000217d42f8666b13550c6.

thanks