* Move instance variable to avoid `NoMethodError`
Methods for `role` and `system` properties are dynamically generated and
return values from the `@virtualization_data` Mash. Therefor, we must
ensure `@virtualization_data` exists before calling these methods.
* Move supports logic to `supports platform: linux`
Signed-off-by: Jerry Aldrich <jerryaldrichiii@gmail.com>
