Separate requirements for documents tox job

This commit separates the requirements libraries for the docs job in
tox.ini. The latest sphinx doesn't work in Python2 environments anymore.
So, we need to split that into the test and docs jobs.

Change-Id: I7255cd9af0dfb5c1f66c1aa65d0ddfb144079836

doc/requirements.txt

@@ -0,0 +1,6 @@
+# The order of packages is significant, because pip processes them in the order
+# of appearance. Changing the order has an impact on the overall integration
+# process, which may cause wedges in the gate later.
+openstackdocstheme>=1.18.1 # Apache-2.0
+reno>=2.5.0 # Apache-2.0
+sphinx!=1.6.6,!=1.6.7,>=1.6.2 # BSD

test-requirements.txt

@@ -4,11 +4,8 @@
 
 hacking<0.11,>=0.10.0
 
-docutils>=0.11 # OSI-Approved Open Source, Public Domain
-doc8>=0.6.0 # Apache-2.0
 fixtures>=3.0.0 # Apache-2.0/BSD
 python-subunit>=0.0.18 # Apache-2.0/BSD
-sphinx>=1.6.2 # BSD
 oslotest>=1.10.0 # Apache-2.0
 testrepository>=0.0.18 # Apache-2.0/BSD
 testscenarios>=0.4 # Apache-2.0/BSD
@@ -16,7 +13,5 @@ testtools>=1.4.0 # MIT
 PyMySQL>=0.7.6 # MIT License
 psycopg2>=2.5 # LGPL/ZPL
 stestr>=1.0.0 # Apache-2.0
-reno>=1.8.0 # Apache-2.0
 oslo.concurrency>=3.8.0 # Apache-2.0
 six>=1.9.0 # MIT
-openstackdocstheme>=1.11.0 # Apache-2.0

tox.ini

@@ -41,6 +41,10 @@ commands =
 
 [testenv:docs]
 basepython = python3
+deps =
+  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -r{toxinidir}/requirements.txt
+  -r{toxinidir}/doc/requirements.txt
 commands = python setup.py build_sphinx
 
 [testenv:debug]
@@ -49,6 +53,10 @@ commands = oslo_debug_helper {posargs}
 
 [testenv:releasenotes]
 basepython = python3
+deps =
+  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -r{toxinidir}/requirements.txt
+  -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -a -E -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [flake8]