Stop testing python 2 in tox and zuul.

Remove python 2 from envlist parameter. Check the link:

https://etherpad.openstack.org/p/drop-python2-support

The plan is drop the python 2 support from OpenStack in Ussuri release.
Remove the zuul jobs.

Note that the (non-voting) openstackclient-check-plugins job is still
running under py2 at this time. That will need to be fixed in the
python/openstackclient repository where the job is defined.

Change-Id: I3148db053b9ef0fcf7dc88e5cc075d974c93d819

.zuul.yaml

@@ -5,28 +5,6 @@
       Run unit tests for OpenStackClient with master branch of important libs.
 
       Takes advantage of the base tox job's install-siblings feature.
-    required-projects:
-      - openstack/cliff
-      - openstack/keystoneauth
-      - openstack/openstacksdk
-      - openstack/os-client-config
-      - openstack/osc-lib
-      - openstack/python-openstackclient
-    vars:
-      tox_envlist: py27
-      # Set work dir to openstackclient so that if it's triggered by one of the
-      # other repos the tests will run in the same place
-      zuul_work_dir: src/opendev.org/openstack/python-openstackclient
-
-- job:
-    name: osc-tox-py27-tips
-    parent: openstack-tox-py27
-    description: |
-      Run unit tests for OpenStackClient with master branch of important libs.
-
-      Takes advantage of the base tox job's install-siblings feature.
-    # The job only tests the latest and shouldn't be run on the stable branches
-    branches: ^(?!stable)
     required-projects:
       - openstack/cliff
       - openstack/keystoneauth
@@ -154,7 +132,6 @@
       - openstack/python-openstackclient
     vars:
       devstack_localrc:
-        USE_PYTHON3: true
         LIBS_FROM_GIT: python-openstackclient,openstacksdk,osc-lib,os-client-config
         # This is insufficient, but leaving it here as a reminder of what may
         # someday be all we need to make this work
@@ -179,11 +156,9 @@
     name: osc-tox-unit-tips
     check:
       jobs:
-        - osc-tox-py27-tips
         - osc-tox-py36-tips
     gate:
       jobs:
-        - osc-tox-py27-tips
         - osc-tox-py36-tips
 
 - project:
@@ -192,12 +167,10 @@
       - osc-tox-unit-tips
       - openstack-cover-jobs
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs
-      - openstack-python3-train-jobs
+      - openstack-python3-ussuri-jobs
       - publish-openstack-docs-pti
       - check-requirements
       - release-notes-jobs-python3
-      - lib-forward-testing
       - lib-forward-testing-python3
     check:
       jobs:

tox.ini

@@ -1,10 +1,15 @@
 [tox]
 minversion = 2.3
-envlist = py27,py37,pep8
+envlist = py37,pep8
 skipdist = True
+# Automatic envs (pyXX) will only use the python version appropriate to that
+# env and ignore basepython inherited from [testenv] if we set
+# ignore_basepython_conflict.
+ignore_basepython_conflict = True
 
 [testenv]
 usedevelop = True
+basepython = python3
 install_command = pip install {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
          OS_STDOUT_CAPTURE=1
@@ -24,7 +29,6 @@ commands =
   {toxinidir}/tools/fast8.sh
 
 [testenv:pep8]
-basepython = python3
 commands =
     flake8
     bandit -r openstackclient -x tests -s B105,B106,B107,B401,B404,B603,B606,B607,B110,B605,B101
@@ -86,7 +90,6 @@ commands =
     stestr run {posargs}
 
 [testenv:venv]
-basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/requirements.txt
@@ -94,7 +97,6 @@ deps =
 commands = {posargs}
 
 [testenv:cover]
-basepython = python3
 setenv =
     VIRTUAL_ENV={envdir}
     PYTHON=coverage run --source openstackclient --parallel-mode
@@ -110,7 +112,6 @@ commands =
     oslo_debug_helper -t openstackclient/tests {posargs}
 
 [testenv:docs]
-basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/requirements.txt
@@ -122,7 +123,6 @@ commands =
   whereto doc/build/html/.htaccess doc/test/redirect-tests.txt
 
 [testenv:releasenotes]
-basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/doc/requirements.txt
@@ -140,7 +140,6 @@ import-order-style = pep8
 application_import_names = openstackclient
 
 [testenv:lower-constraints]
-basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt