Add auto-cleanup of rbenv-ruby 2.2.0
Add auto-cleanup of rbenv-ruby 2.2.0

So that it will also be cleaned up on machines that switch from using
`govuk_rbenv::all` to just `govuk_rbenv`

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet