1. The html_last_updated_fmt sphinx setting was providing a byte string
where sphinx expected a str, which produced warnings (and therefore
failures):
WARNING: The config value `html_last_updated_fmt' has type `bytes', expected to ['str'].
The solution provided is copied from cinder's solution[1].
2. The .keys() method in python 3 returns a dict_keys object rather than
a list and it does not include a .sort() method. This patch swaps
.sort() out for the global function sorted() which works in both python
2 and python 3.
This came up because on some newer distros that don't install python 2
by default, virtualenv defaults to creating a python 3 environment when
none is specified.
[1] https://review.openstack.org/#/c/433081
Change-Id: I68b796fa2e33fd6c3df67b542def31e6ba620944
c7ab7c5677