Since then all builds fail very early with the error below - which is not related to oVirt.

Removing image: sha256:f8e5aa8e979155e074411bfef9adade6cdcdf3a5a2eb1d5ad2dbf0288d585ffa, force=True
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/docker/api/client.py", line 222, in _raise_for_status
    response.raise_for_status()
  File "/usr/lib/python3.6/site-packages/requests/models.py", line 893, in raise_for_status
    raise HTTPError(http_error_msg, response=self)

requests.exceptions.HTTPError: 404 Client Error: Not Found for url: http+docker://localunixsocket/v1.30/images/sha256:f8e5aa8e979155e074411bfef9adade6cdcdf3a5a2eb1d5ad2dbf0288d585ffa?force=True&noprune=False

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/jenkins/workspace/ovirt-system-tests_manual/jenkins/scripts/docker_cleanup.py", line 349, in <module>
    main()
  File "/home/jenkins/workspace/ovirt-system-tests_manual/jenkins/scripts/docker_cleanup.py", line 37, in main
    safe_image_cleanup(client, whitelisted_repos)
  File "/home/jenkins/workspace/ovirt-system-tests_manual/jenkins/scripts/docker_cleanup.py", line 107, in safe_image_cleanup
    _safe_rm(client, parent)
  File "/home/jenkins/workspace/ovirt-system-tests_manual/jenkins/scripts/docker_cleanup.py", line 329, in _safe_rm
    client.images.remove(image_id, force=force)
  File "/usr/lib/python3.6/site-packages/docker/models/images.py", line 288, in remove
    self.client.api.remove_image(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/docker/utils/decorators.py", line 19, in wrapped
    return f(self, resource_id, *args, **kwargs)
  File "/usr/lib/python3.6/site-packages/docker/api/image.py", line 481, in remove_image
    return self._result(res, True)
  File "/usr/lib/python3.6/site-packages/docker/api/client.py", line 228, in _result
    self._raise_for_status(response)
  File "/usr/lib/python3.6/site-packages/docker/api/client.py", line 224, in _raise_for_status
    raise create_api_error_from_http_exception(e)
  File "/usr/lib/python3.6/site-packages/docker/errors.py", line 31, in create_api_error_from_http_exception
    raise cls(e, response=response, explanation=explanation)
docker.errors.NotFound: 404 Client Error: Not Found ("reference does not exist")

Aborting.

Build step 'Execute shell' marked build as failure