client: add a --rm option to run the container

This fixes the case where the playbook died and never removed the
container. So now, once the container exits it will remove itself from
the container list.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1568157
Signed-off-by: Sébastien Han <seb@redhat.com>

roles/ceph-client/tasks/create_users_keys.yml

@@ -15,6 +15,7 @@
 - name: run a dummy container (sleep 300) from where we can create pool(s)/key(s)
   command: >
     docker run \
+    --rm \
     -d \
     -v {{ ceph_conf_key_directory }}:{{ ceph_conf_key_directory }} \
     --name ceph-create-keys \