Fix for nova-compute service not beeing started.

nova-compute service should be started after nova::compute recipe will
finish its work.

Change-Id: I9dac760c901d04e465a20ced363242fab0b93a03
Enforce keystone v2.0 usage

See https://review.openstack.org/#/c/24386/
and https://bugs.launchpad.net/nova/+bug/1154809

Change-Id: Id1f5950d468d4af4c7a78f207e7edb466b6c3a49