logging-curator fails to run following cluster logging upgrade to v3.11.374

Issue

• Following a Cluster Logging upgrade to v3.11.374, the logging-curator pod ends in Error/Failed state, sreaming the following content in the pod logs:

  $ oc -n openshift-logging logs logging-curator-1611822600-jp2mh
  2021-01-28 08:30:13,271 INFO  Found curator configuration in [/etc/curator/settings/config.yaml]
  2021-01-28 08:30:13,278 INFO  Converting config file.
  Traceback (most recent call last):
  File "/usr/bin/curator", line 9, in <module>
    load_entry_point('elasticsearch-curator==5.2.0', 'console_scripts', 'curator')()
  File "/usr/lib/python2.7/site-packages/click/core.py", line 722, in __call__
    return self.main(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/click/core.py", line 697, in main
    rv = self.invoke(ctx)
  File "/usr/lib/python2.7/site-packages/click/core.py", line 895, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/lib/python2.7/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/curator/cli.py", line 211, in cli
    run(config, action_file, dry_run)
  File "/usr/lib/python2.7/site-packages/curator/cli.py", line 158, in run
    client = get_client(**client_args)
  File "/usr/lib/python2.7/site-packages/curator/utils.py", line 800, in get_client
    'Error: {0}'.format(e)
  elasticsearch.exceptions.ElasticsearchException: Unable to create client connection to Elasticsearch.  Error: 'module' object has no attribute 'ensure_str'