Change PowerVM version to an int
Change PowerVM version to an int

Nova now requires the hypervisor version to be an int, so
change the PowerVM value to be an int.

Change-Id: I41cae9eeb086a46b917f24809f858de1cd76711c

stackforge/nova-powervm,stackforge/nova-powervm,openstack/nova-powervm,openstack/nova-powervm