docker2podman: make images pulling optional

This commit makes the images pulling skipped if podman isn't installed
on the machine.

In OSP context, the podman installation is done later in the workflow,
it means all `podman pull` commands will fail.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1849559

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
(cherry picked from commit 37b20b6525)

infrastructure-playbooks/docker-to-podman.yml

@@ -84,6 +84,15 @@
       tags: with_pkg
       when: not is_atomic | bool
 
+    - name: check podman presence
+      command: command -v podman
+      register: podman_presence
+      changed_when: false
+      failed_when: false
+
+    - name: pulling images from docker daemon
+      when: podman_presence.rc == 0
+      block:
         - name: "pulling {{ ceph_docker_registry }}/{{ ceph_docker_image }}:{{ ceph_docker_image_tag }} image from docker daemon"
           command: "{{ timeout_command }} {{ container_binary }} pull docker-daemon:{{ ceph_docker_registry }}/{{ ceph_docker_image }}:{{ ceph_docker_image_tag }}"
           changed_when: false