adding compute driver for ubuntu, stock nova-compute package does not have this config in nova.conf, will be no-op on havana as it is already present

Change-Id: Id8fcf0e8eb55e0624c60d9a9aad1aee862f75b5e
Merge "adding compute driver for ubuntu, stock nova-compute package does not have this config in nova.conf, will be no-op on havana as it is already present"