[ussuri][goal] Cleanup drop python 2.7 support

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

Complete discussion & schedule can be found in
- http://lists.openstack.org/pipermail/openstack-discuss/2019-October/010142.html
- https://etherpad.openstack.org/p/drop-python2-support

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

this removes some cruft that can be removed now:
* cruft in setup.cfg and setup.py
* tox.ini: Add ignore_basepython_conflict and increase minversion
  for that
* Python 2/3 specific requirements, the repo is Python 3 only.

Change-Id: Iae68e58c82a180eb771bef00a3f44fd28abe5fae

requirements.txt

@@ -28,8 +28,7 @@ six>=1.9.0 # MIT
 stevedore>=1.5.0 # Apache-2.0
 tooz>=1.28.0 # Apache-2.0
 voluptuous>=0.11.1 # BSD License
-influxdb>=5.1.0,!=5.2.0,!=5.2.1,!=5.2.2;python_version<'3.0'  # MIT
-influxdb>=5.1.0;python_version>='3.0'  # MIT
+influxdb>=5.1.0 # MIT
 Flask>=1.0.2 # BSD
 Flask-RESTful>=0.3.5 # BSD
 cotyledon>=1.5.0 # Apache-2.0

setup.cfg

@@ -6,6 +6,7 @@ description-file =
 author = OpenStack
 author-email = openstack-discuss@lists.openstack.org
 home-page = https://docs.openstack.org/cloudkitty/latest
+python-requires = >=3.6
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -74,12 +75,3 @@ cloudkitty.storage.hybrid.backends =
 cloudkitty.output.writers =
     osrf = cloudkitty.writer.osrf:OSRFBackend
     csv = cloudkitty.writer.csv_map:CSVMapped
-
-[build_sphinx]
-all_files = 1
-build-dir = doc/build
-source-dir = doc/source
-
-[global]
-setup-hooks =
-    pbr.hooks.setup_hook

setup.py

@@ -16,14 +16,6 @@
 # THIS FILE IS MANAGED BY THE GLOBAL REQUIREMENTS REPO - DO NOT EDIT
 import setuptools
 
-# In python < 2.7.4, a lazy loading of package `pbr` will break
-# setuptools if some other modules registered functions in `atexit`.
-# solution from: http://bugs.python.org/issue15881#msg170215
-try:
-    import multiprocessing  # noqa
-except ImportError:
-    pass
-
 setuptools.setup(
     setup_requires=['pbr>=2.0.0'],
     pbr=True)

test-requirements.txt

@@ -12,7 +12,7 @@ gabbi>=1.26.1 # Apache-2.0
 testscenarios>=0.4 # Apache-2.0/BSD
 stestr>=2.0.0 # Apache-2.0
 mock>=1.2 # BSD
-sphinx>=1.8.0,!=2.1.0;python_version>='3.4' # BSD
+sphinx>=1.8.0,!=2.1.0 # BSD
 openstackdocstheme>=1.30.0 # Apache-2.0
 oslotest>=1.10.0 # Apache-2.0
 sphinxcontrib-httpdomain>=1.6.0 # BSD

tox.ini

@@ -1,7 +1,8 @@
 [tox]
-minversion = 2.0
+minversion = 3.1.0
 skipsdist = True
 envlist = py36,py37,pep8
+ignore_basepython_conflict = True
 
 [testenv]
 basepython = python3