[ussuri][goal] Drop python 2.7 support

OpenStack is dropping the py2.7 support in ussuri cycle.

specs repo either has py27 job or requirement or tox env.

Update requirements for Sphinx that works with python3, this needs
updating from oslosphinx to openstackdocstheme as well.

Ussuri Communtiy-wide goal:
https://governance.openstack.org/tc/goals/selected/ussuri/drop-py27.html

Change-Id: I1a1bd69ef048ba3ccd0b8188742b9bbbc07f3bbc

.zuul.yaml

@@ -3,7 +3,7 @@
       - openstack-specs-jobs
     check:
       jobs:
-        - openstack-tox-py27
+        - openstack-tox-py37
     gate:
       jobs:
-        - openstack-tox-py27
+        - openstack-tox-py37

doc/source/conf.py

@@ -24,7 +24,7 @@ sys.path.insert(0, os.path.abspath('../..'))
 extensions = [
     'sphinx.ext.autodoc',
     #'sphinx.ext.intersphinx',
-    'oslosphinx',
+    'openstackdocstheme',
     'yasfb',
 ]
 
@@ -51,6 +51,11 @@ master_doc = 'index'
 project = u'telemetry-specs'
 copyright = u'%s, OpenStack Foundation' % datetime.date.today().year
 
+# openstackdocstheme options
+repository_name = 'openstack/python-glanceclient'
+use_storyboard = True
+html_theme = 'openstackdocs'
+
 # If true, '()' will be appended to :func: etc. cross-reference text.
 add_function_parentheses = True
 

requirements.txt

@@ -1,6 +1,6 @@
-oslosphinx
-pbr>=0.6,!=0.7,<1.0
-sphinx>=1.1.2,<1.2
+pbr!=2.1.0,>=2.0.0 # Apache-2.0
+sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.5 # BSD
+openstackdocstheme>=1.22
 testrepository>=0.0.18
 testtools>=0.9.34
 yasfb>=0.5.1

tox.ini

@@ -1,9 +1,11 @@
 [tox]
-minversion = 1.6
-envlist = docs,py27
+minversion = 3.1.1
+envlist = docs,pep8
 skipsdist = True
+ignore_basepython_conflict = True
 
 [testenv]
+basepython = python3
 usedevelop = True
 setenv = VIRTUAL_ENV={envdir}
 install_command = pip install -U {opts} {packages}