Simplify logic in docker detection for docker-rm role

Fix and simplify the logic that detects if Docker is installed on the
host.

Change-Id: I641f7546afeabf222bcbe148fbe6cc94547f5c92

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

@@ -4,14 +4,11 @@
     path: /usr/bin/docker
   register: docker_path_stat
 
-- set_fact:
-    docker_installed: "{{ docker_path_stat.results | map(attribute='stat') | map(attribute='exists') is any }}"
-
 - name: remove "{{ containers_to_rm|join(', ') }}" containers
   docker_container:
     name: "{{ item }}"
     state: absent
   when:
     - container_cli == 'podman'
-    - docker_installed
+    - docker_path_stat.stat.exists
   with_items: "{{ containers_to_rm }}"