Cleanup doc dependencies

This creates a dedicated doc/requirements.txt for doc-only
dependencies like sphinx packages so we can decouple those
from the test-requirements.txt.

As a result, the missing oslo.serialization runtime dependency
is added (I used the same version that python-novaclient uses).

Due to change If558f184c959e4b63b56dec3ca1571d1034cfe5c in the
openstack/requirements repo, in order to pass the
requirements-check job we have to specify both the py27 and py3
versions for sphinx.

Change-Id: I8bc3330a456f8bb76a17c4277a094a64fe9be449

doc/requirements.txt

@@ -0,0 +1,7 @@
+# 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
+sphinx!=1.6.6,!=1.6.7,>=1.6.5,<2.0.0;python_version=='2.7' # BSD
+sphinx!=1.6.6,!=1.6.7,>=1.6.5;python_version>='3.4' # BSD

requirements.txt

@@ -6,6 +6,7 @@ Babel!=2.4.0,>=2.5.3 # BSD
 cliff!=2.9.0,>=2.11.0 # Apache-2.0
 osc-lib>=1.10.0 # Apache-2.0
 oslo.i18n>=3.20.0 # Apache-2.0
+oslo.serialization!=2.19.1,>=2.18.0 # Apache-2.0
 oslo.utils>=3.36.0 # Apache-2.0
 pbr!=2.1.0,>=3.1.1 # Apache-2.0
 PrettyTable<0.8,>=0.7.2 # BSD

test-requirements.txt

@@ -6,10 +6,8 @@ coverage!=4.4,>=4.0 # Apache-2.0
 fixtures>=3.0.0 # Apache-2.0/BSD
 hacking>=1.1.0,<1.2.0 # Apache-2.0
 mock>=2.0.0 # BSD
-openstackdocstheme>=1.18.1 # Apache-2.0
 oslotest>=3.2.0 # Apache-2.0
 python-subunit>=1.0.0 # Apache-2.0/BSD
-sphinx!=1.6.6,!=1.6.7,>=1.6.5 # BSD
 stestr>=2.0.0 # Apache-2.0
 testscenarios>=0.4 # Apache-2.0/BSD
 testtools>=2.2.0 # MIT

tox.ini

@@ -42,6 +42,10 @@ commands =
 
 [testenv:docs]
 basepython = python3
+deps =
+  -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
+  -r{toxinidir}/requirements.txt
+  -r{toxinidir}/doc/requirements.txt
 commands = python setup.py build_sphinx
 
 [testenv:debug]