fix check exists download cache (#5776)

roles/download/tasks/download_container.yml

@@ -42,7 +42,7 @@
 
     - name: Stop if image not in cache on ansible host when download_force_cache=true
       assert:
-        that: not image_is_cached
+        that: image_is_cached
         msg: "Image cache file {{ image_path_cached }} not found for {{ image_reponame }} on localhost"
       when:
         - download_force_cache