Ensure docker is running before dropping containers

It might happen we have docker binary installed, while the docker
service isn't active/running. This would make the playbook fail,
while it's not a valid failure.

Change-Id: I3f3011e6855b38828644b94fac3f5e88edfc6d1a

roles/tripleo-docker-rm/tasks/main.yaml

@@ -4,6 +4,12 @@
     path: /usr/bin/docker
   register: docker_path_stat
 
+- name: Ensure docker service is running
+  when: docker_path_stat.stat.exists
+  systemd:
+    name: docker
+  register: docker_service_state
+
 - name: remove "{{ containers_to_rm|join(', ') }}" containers
   docker_container:
     name: "{{ item }}"
@@ -11,4 +17,5 @@
   when:
     - container_cli == 'podman'
     - docker_path_stat.stat.exists
+    - docker_service_state.status['SubState'] == 'running'
   with_items: "{{ containers_to_rm }}"