Add Pillow for stevedore doc build

As part of setting up gate jobs for stevedore, we have turned on
a doc build gate job. That job is failing because it can't install
Pillow. Nothing else uses Pillow, and it is not a runtime dependency
of stevedore.

Change-Id: I96c80ce571bae71ef1b867b0c4f60572fa9a4c5c
Trollius: allow version 0.2 and later

As the author of the Trollius module, I would like to use newer
versions. In version 0.2, the API changed a little bit ("yield
From(...)" instead of "yield ..."), but the change is backward
compatible (yield ...  is still accepted).

Change-Id: I65559d725f443cd2097ab09bf6a0f1adb81d1153
Don't use flake8: noqa

A line with "# flake8: noqa" disables pep8 for the entire file.
Use "# noqa" for a line.

Change-Id: Id0e4b98f02149113963af2c1da1b42d667d139d5
Merge "Don't use flake8: noqa"
Merge "Add Pillow for stevedore doc build"
Remove old pep8, pyflakes and flake8 versions

The previous patch (Ia3495102a9d096c09802b9c079a8dc7ec1f65530) just
added new versions in order to not create a backwards incompatible
change, this removes the old versions and adds a new version of pep8 in
a backwards compatible way.

Change-Id: Ibdaa3724cceec8e53580ff2960a526fa54ec4b0a
Merge "Trollius: allow version 0.2 and later"
require new setuptools

Bug #1290562 believes new setuptools fixes the the issue now,
try a new version to see.

Change-Id: Ifcc7bf4b0e94d96fca5d87ee85de788564b4aba6
Update openstack-doc-tools for Documentation repos

Version 0.11 is current version. This new version
is required to properly build and publish the various
OpenStack documentation repos like operations-guide, api-site and
openstack-manuals.

Change-Id: I37540b106d17d638cf8c1b5a4e9132c18d3f2168
Merge "Update openstack-doc-tools for Documentation repos"
Merge "Remove old pep8, pyflakes and flake8 versions"
Upgrade six requirement to 1.6.0

This is needed for having URL SplitResult support.

Change-Id: I8486f8d6e07d577027856a15d60027f24cbe8782
Merge "require new setuptools"
Merge "Upgrade six requirement to 1.6.0"