Update Vagrantfile

[wizonesolutions]

It's giving a few warnings because Vagrant 1.1+. Copy/pasted:

There were warnings and/or errors while loading your Vagrantfile.
Your Vagrantfile was written for an earlier version of Vagrant,
and while Vagrant does the best it can to remain backwards
compatible, there are some cases where things have changed
significantly enough to warrant a message. These messages are
shown below.

Warnings:
* `config.vm.customize` calls are VirtualBox-specific. If you're
using any other provider, you'll have to use config.vm.provider in a
v2 configuration block.
* The 'v-root' shared folders have been renamed to 'vagrant-root'.
Assuming you meant 'vagrant-root'...

[mgifford]

Think that's fixed with this patch:
mgifford@07052f4

It's all bundled with the same pull request though.