Add support for new doc PTI jobs

Implement optional cleanup to support the new PTI jobs
for documentation which won't use tox anymore.

Docs tox environment will still available for developers but
it is no loger used in the gate to construct the documentation.

See http://lists.openstack.org/pipermail/openstack-dev/2017-December/125710.html

Change-Id: Ib4a380eec3c9f286dc563f2b81c6b27f92467cf3

doc/requirements.txt

@@ -0,0 +1,2 @@
+sphinx>=1.6.2
+openstackdocstheme>=1.11.0  # Apache-2.0

test-requirements.txt

@@ -3,7 +3,6 @@ pep8==1.5.7
 pyflakes==0.8.1
 flake8==2.2.4
 docutils>=0.11  # OSI-Approved Open Source, Public Domain
-sphinx>=1.6.2
 httmock>=1.2.4
 mock
 oslotest>=1.2.0 # Apache-2.0
@@ -12,4 +11,3 @@ testrepository>=0.0.18
 testtools>=0.9.34
 pep257>=0.5.0
 PyMySQL>=0.6.2,!=0.6.4
-openstackdocstheme>=1.11.0  # Apache-2.0

tox.ini

@@ -64,7 +64,8 @@ commands = python setup.py testr --coverage \
 commands = {toxinidir}/tools/cover.sh {posargs}
 
 [testenv:docs]
-commands = python setup.py build_sphinx {posargs}
+deps = -r{toxinidir}/doc/requirements.txt
+commands = sphinx-build -b html doc/source doc/build/html
 
 [flake8]
 # E125 continuation line does not distinguish itself from next logical line