Destroy pre existing VM's regardless of Provisioner

Ironic doesn't require these to be shutdown but leaving them running
leads to nodes running in CI from previous tests hitting the API of
services in the current test. The resulting errors and trace-backs
are confusing when debugging problems.

Change-Id: Ia5bccd69af0f92c14db901f09b32521821ba567d
Merge "Destroy pre existing VM's regardless of Provisioner"