Gem kitchen-vagrant uses option vagrantfiles [0] to define other
Vagrantfiles to be merged with default one. Under the hood it uses
require on top of main Vagrantfile. When you configure persistent
storage plugin in one of vagrantfiles [0] plugin will be disabled
due to load order and merging [1].
[0] https://github.com/test-kitchen/kitchen-vagrant#-vagrantfiles
[1] https://www.vagrantup.com/docs/vagrantfile/#load-order