purge: do not try to stop docker when binary is podman

If the container binary is podman, we shouldn't try to stop docker here.

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
(cherry picked from commit b18476a1a6)

infrastructure-playbooks/purge-docker-cluster.yml

@@ -550,7 +550,9 @@
         name: docker
         state: stopped
         enabled: no
-      when: not is_atomic
+      when:
+        - not is_atomic
+        - container_binary == 'docker'
       ignore_errors: true
 
     - name: remove docker on debian/ubuntu