Use Vagrant's Ansible provisioner

I happened upon your repo and noticed they weren't using Vagrant's built-in support for Ansible using the [Ansible Provisioner](http://docs.vagrantup.com/v2/provisioning/ansible.html). Thought you might be interested in using this provisioner, since it simplifies the config.

Vagrant will generate a host file automatically (with the correct port numbers for ssh), and the ansible config file can be simplified. You can also pass fsid and monitor_secret in the Vagrantfile, so the user doesn't have to edit it themselves.