Create and attach other required openstack resources
Rather than expecting a user to create keypair prior to run
infra-ansible, just make infra-ansible to create the keypair
per the variable passed as keypair_contents on infra_config.yml.
Role provision_infra_servers not only creates instances, but also
volumes and now kepairs, thus also renaming the provision_infra_servers
role and playbook to setup_openstack_resources.