Fix documentation builds

This patch does a few things to fix the documentation builds for
this project

- Move requirements to doc/requirements.txt for building docs to
  avoid installing extra dependencies.
- Bump sphinx version to a newer release which is compatible with
  sphinxcontrib-programoutput
- Remove default theme option to use the latest Sphinx theme that
  is shipped directly from upstream.
- Bumped basepython for documentation jobs to Python 3.

These are all squashed because the job is currently broken.

Change-Id: Ib998923a5daaa5e9d3ddc748b76b6304e5c39b22

doc/requirements.txt

@@ -0,0 +1,2 @@
+sphinx>=1.6.1
+sphinxcontrib-programoutput

doc/source/conf.py

@@ -92,7 +92,7 @@ pygments_style = 'sphinx'
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'default'
+#html_theme = 'default'
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
@@ -121,7 +121,7 @@ html_theme = 'default'
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['_static']
+html_static_path = []
 
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.

test-requirements.txt

@@ -5,9 +5,7 @@ fixtures>=0.3.12
 python-subunit
 pyOpenSSL
 statsd>=1.0.0,<3.0
-sphinx>=1.1.2,<1.2
 testrepository>=0.0.13
 testresources
 testscenarios
 testtools>=0.9.27
-sphinxcontrib-programoutput

tox.ini

@@ -33,7 +33,11 @@ show-source = true
 ignore = E123,E125,E129,H
 
 [testenv:docs]
-commands = python setup.py build_sphinx
+basepython = python3
+deps =
+  -r{toxinidir}/doc/requirements.txt
+commands =
+  sphinx-build -E -W -d doc/build/doctrees -b html doc/source/ doc/build/html
 
 [testenv:bindep]
 # Do not install any requirements. We want this to be fast and work even if