Make all tools require python3 and remove python2 testing

Now that the last tool that needed python2 has been checked/fixed lets
remove all the python2 infrastructure and make all library users exit if
run under python2

Change-Id: I20184300f0a6cb6d230428cafc49f1b917376380

.zuul.d/project.yaml

@@ -5,13 +5,11 @@
       - openstack-python36-jobs
     check:
       jobs:
-        - openstack-tox-py27
         - openstack-tox-linters
         - election-tox-ci-checks-review
         - election-tox-ci-checks-election
     gate:
       jobs:
-        - openstack-tox-py27
         - openstack-tox-linters
         - election-tox-ci-checks-election
     post:

openstack_election/__init__.py

@@ -0,0 +1 @@
+from . import require_py3  # noqa

openstack_election/cmds/setup_election_config.py

@@ -23,8 +23,6 @@ import yaml
 from collections import OrderedDict
 
 from openstack_election.config import ISO_FMT
-# Because python 2 has a revered OrderedDict ?
-import openstack_election.require_py3  # noqa
 from openstack_election import utils
 
 ONE_WEEK = datetime.timedelta(weeks=1)

tox.ini

@@ -22,10 +22,6 @@ commands = yamllint configuration.yaml
 [testenv:venv]
 commands = {posargs}
 
-[testenv:venv2]
-basepython = python2
-commands = {posargs}
-
 [testenv:docs]
 commands = sphinx-build -v -W -b html -d doc/build/doctrees doc/source doc/build/html