Satellite 6 update or upgrade fails on pulp-manage-db step with AttributeError: 'NoneType' object has no attribute 'critical'

Issue

• Updating or upgrading between Satellite 6 versions fails with "AttributeError: 'NoneType' object has no attribute 'critical'".

[ERROR 2018-02-05 17:43:32 main] Upgrade step migrate_pulp failed. Check logs for more information.
[DEBUG 2018-02-05 17:43:32 main] Exit with status code: 1 (signal was 1)
[ERROR 2018-02-05 17:43:32 main] Errors encountered during run:
[ERROR 2018-02-05 17:43:32 main] Traceback (most recent call last):
  File "/bin/pulp-manage-db", line 9, in <module>
    load_entry_point('pulp-server==2.8.7.18', 'console_scripts', 'pulp-manage-db')()
  File "/usr/lib/python2.7/site-packages/pulp/server/db/manage.py", line 245, in main
    _logger.critical(str(e))
AttributeError: 'NoneType' object has no attribute 'critical'

• Pulp services fail to start with "AttributeError: 'NoneType' object has no attribute 'critical'".