(gh-477) enables root for non-root users on ec2 hypervisor

- root login is not possible on ubuntu-amis
- provision is not possible without root

This Patch enables root when the host['user'] differs from "root"
I kind of dislike this methodology generally, and prefer using cloud-init or something of the like, ie. passing in user data to allow root. Or at least baking into into the image instead (pretty easy with packer & its aws user data option). Although its fairly innocuous I guess. More because while this might work now, later someone could change the underlying the implementation to change how root gets locked out, cloud-init is the real API in that perspective I guess.

Having said that most of the work is done, just saying there is potentially a better way than doing this all manually.