Cron – Let’s Encrypt certbot-auto setuptools version error when run from cron

CentOS 6, certbot 0.16.0. When I run it manually as root (not by sudo) everything works. When I setup /etc/crontab to run it automatically it returns an error:

Error: couldn't get currently installed version for //.local/share/letsencrypt/bin/letsencrypt: 
//.local/share/letsencrypt/lib64/python2.6/site-packages/cryptography/__init__.py:26: DeprecationWarning: Python 2.6 is no longer supported by the   Python core team, please upgrade your Python. A future version of cryptography will drop support for Python 2.6
  DeprecationWarning
An unexpected error occurred:
ContextualVersionConflict: (setuptools 0.9.8 (/.local/share/letsencrypt/lib/python2.6/site-packages), Requirement.parse('setuptools>=1.0'), set(['certbot']))
Please see the logfile '/tmp/tmp5jOtY3' for more details.`

cat /tmp/tmp5jOtY3

2017-07-31 11:37:02,325:DEBUG:certbot.log:Exiting abnormally:
Traceback (most recent call last):
  File "//.local/share/letsencrypt/bin/letsencrypt", line 11, in <module>
sys.exit(main())
  File "//.local/share/letsencrypt/lib64/python2.6/site-packages/certbot/main.py", line 723, in main
plugins = plugins_disco.PluginsRegistry.find_all()
  File "//.local/share/letsencrypt/lib64/python2.6/site-packages/certbot/plugins/disco.py", line 203, in find_all
plugin_ep = PluginEntryPoint(entry_point)
  File "//.local/share/letsencrypt/lib64/python2.6/site-packages/certbot/plugins/disco.py", line 50, in __init__
self.plugin_cls = entry_point.load()
  File "//.local/share/letsencrypt/lib64/python2.6/site-packages/pkg_resources/__init__.py", line 2201, in load
self.require(*args, **kwargs)
  File "//.local/share/letsencrypt/lib64/python2.6/site-packages/pkg_resources/__init__.py", line 2218, in require
items = working_set.resolve(reqs, env, installer)
  File "//.local/share/letsencrypt/lib64/python2.6/site-packages/pkg_resources/__init__.py", line 835, in resolve
raise VersionConflict(dist, req).with_context(dependent_req)
ContextualVersionConflict: (setuptools 0.9.8 (/.local/share/letsencrypt/lib/python2.6/site-packages), Requirement.parse('setuptools>=1.0'), set(['certbot']))

cat /etc/crontab

SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/

27  18  *  *  * root /opt/certbot-auto renew --quiet --no-self-upgrade

I tried Let's Encrypt community and found someone having this exact problem, but the only help offered was migration to bash script. I would prefer to fix the official script instead.

Let's Encrypt forum post