restructure Vagrant, making recipe lean and easy to augment

This is a follow-up to PR #520, per @dcapwell and @haoyuan suggestion. 

Will be the basis to the coming docker provider.

Tested on AWS, OpenStack, and Virtualbox.
Don't know how this comment got up here.... 

The code was

`Init = "ufs/#{Ufs}"+"/init.sh"`

The comment was saying that you could do

`Init = "ufs/#{Ufs}/init.sh"`