ppc64le: Install docker and start the docker service for builds
ppc64le: Install docker and start the docker service for builds

We fail to log in to the rdoproject.org registry as docker is not
installed. This patch adds docker to the list of yum installs and
starts the docker service for the ppc64le container build job.

Change-Id: Ie0a7b6bd33e443087b291136a33aca539ab69e12

redhat-openstack/rdo-infra,rdo-infra/ci-config,redhat-openstack/rdo-infra,rdo-infra/ci-config,rdo-infra/ci-config,redhat-openstack/rdo-infra,redhat-openstack/rdo-infra,rdo-infra/ci-config