Update docs building jobs

Replace build-sphinx job with tox-docs (using template
build-openstack-docs-pti) job as best practice for building docs.
Update tox.ini for this and remove now obsolete section from setup.cfg.

Fix doc building: Remove option from doc/source/conf.py for an unused
directory.

The tox.ini file already contains python3 for releasenotes, update the
job now to do this as well.

Change-Id: I7552c802a99f0338ff6a5a3bba1f24902c55bed4

.zuul.yaml

@@ -1,12 +1,16 @@
 - project:
+    templates:
+      - build-openstack-docs-pti
     check:
       jobs:
-        - build-openstack-releasenotes
+        - build-openstack-releasenotes:
-        - build-openstack-sphinx-docs
+            vars:
+              sphinx_python: python3
     gate:
       jobs:
-        - build-openstack-releasenotes
+        - build-openstack-releasenotes:
-        - build-openstack-sphinx-docs
+            vars:
+              sphinx_python: python3
     post:
       jobs:
         - cbsl-init-upload-git-mirror

doc/source/conf.py

@@ -142,7 +142,7 @@ html_theme = 'classic'
 # 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 = ['_static']
 
 # Add any extra paths that contain custom files (such as robots.txt or
 # .htaccess) here, relative to this directory. These files are copied

setup.cfg

@@ -27,11 +27,6 @@ packages =
 setup-hooks =
     pbr.hooks.setup_hook
 
-[build_sphinx]
-all_files = 1
-build-dir = doc/build
-source-dir = doc/source
-
 [entry_points]
 console_scripts =
   cloudbase-init = cloudbaseinit.shell:main

tox.ini

@@ -41,7 +41,8 @@ commands =
 
 [testenv:docs]
 basepython = python3
-commands = python setup.py build_sphinx
+commands =
+  sphinx-build -a -E -W -d doc/build/doctrees -b html doc/source doc/build/html
 
 [flake8]
 # E125 is deliberately excluded. See https://github.com/jcrocholl/pep8/issues/126