Fix crashing simp_le.py because of missing six package

[igielskv]

In our Debian 10 environment script simple.py started to crash due to missing six module in venv.

Traceback (most recent call last):
  File "/usr/local/sbin/simp_le", line 33, in <module>
    sys.exit(load_entry_point('simp-le-client', 'console_scripts', 'simp_le')())
  File "/opt/simp_le/venv/lib/python3.7/site-packages/pkg_resources/__init__.py", line 489, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/opt/simp_le/venv/lib/python3.7/site-packages/pkg_resources/__init__.py", line 2793, in load_entry_point
    return ep.load()
  File "/opt/simp_le/venv/lib/python3.7/site-packages/pkg_resources/__init__.py", line 2411, in load
    return self.resolve()
  File "/opt/simp_le/venv/lib/python3.7/site-packages/pkg_resources/__init__.py", line 2417, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/opt/simp_le/simp_le.py", line 43, in <module>
    import six

We have mitigated the problem by installing six package in venv.sh

[zenhack]

I pushed a commit to master that adds six to setup.py, which I think is the right solution here; can you confirm that that fixes the issue for you?

[zenhack]

Going to close this; the change I pushed is now part of the 0.19.1 release I just tagged.