Merge pull request #1317 from ibotty/harmonize-docker-names

harmonize docker names

diff --cc infrastructure-playbooks/purge-docker-cluster.yml
Simple merge

diff --cc infrastructure-playbooks/rolling_update.yml
Simple merge

diff --cc infrastructure-playbooks/switch-from-non-containerized-to-containerized-ceph-daemons.yml
Simple merge

diff --cc roles/ceph-mon/tasks/docker/main.yml
Simple merge