Remove calls to Vagrant::Environment#load!

Based on this issue from over two years ago, Vagrant::Environment no
longer has a #load! method and lazy-loads its resources. I've removed
calls to #load! and it seems to fix the problem.

https://github.com/mitchellh/vagrant/issues/236
Merge pull request #13 from teejayvanslyke/master

Remove calls to Vagrant::Environment#load! to make compatible with 1.1.0.dev