Fix docs gate and rtd build

Docs gate was broken due to https://sourceforge.net/p/docutils/bugs/301/

Change-Id: Icdf97e9547da6df0a9b12e1c61413de6690b3ac3

readthedocs.yml

@@ -0,0 +1,4 @@
+python:
+    setup_py_install: true
+
+requirements_file: rtd-requirements.txt

rtd-requirements.txt

@@ -0,0 +1,2 @@
+-r requirements.txt
+-r test-requirements.txt

test-requirements.txt

@@ -7,7 +7,7 @@ coverage>=3.6 # Apache-2.0
 hacking<0.11,>=0.10
 mock>=1.2 # BSD
 oslotest>=1.10.0 # Apache-2.0
-sphinx!=1.2.0,!=1.3b1,<1.3,>=1.1.2 # BSD
+sphinx>=1.5.1 # BSD  -- to avoid https://sourceforge.net/p/docutils/bugs/301/
 sphinxcontrib-httpdomain # BSD
 sphinx_rtd_theme
 testrepository>=0.0.18 # Apache-2.0/BSD

tox.ini

@@ -39,7 +39,6 @@ commands =
     python tools/build_scenario_catalog.py doc/source/catalog.rst
 
 [testenv:docs]
-deps = -r{toxinidir}/doc-requirements.txt
 commands = python setup.py build_sphinx
 
 [testenv:svg2png]