mitchellh/vagrant — pull request #2138 by BreiteSeite (2013-09-06 08:32:30+00:00)
Title: changed Vagrantfile template to use "site.pp"

This seems to be the de facto standard and is used overall in the puppet documentation.
It is also explicitly mentioned in the [Puppet Best Practices Wiki](http://projects.puppetlabs.com/projects/1/wiki/Puppet_Best_Practice2#File-Hierarchy).