Currently, tox-edocs fails with the following error message:
Warning, treated as error:
autodoc: failed to import module 'shell' from module 'glanceclient'; the
following exception was raised:
No module named 'six'
We used to install six in the virtual environment through keystoneauth,
but keystoneauth no longer depends on six. Let's mock six completely in
the context of autodoc.
Change-Id: Ibcf0b9698227a2c22fe991b7516ba5dceabfc607
7c2ab837aa