Drop python 2.7 support and testing

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

python-senlinclient is ready with python 3 and ok to drop the
python 2.7 support.

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://review.opendev.org/#/c/691178/

Change-Id: Id86de6b06dbbf904976b6c845f6a843bbdd2a91b

.zuul.yaml

@@ -13,8 +13,7 @@
     templates:
       - check-requirements
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs
-      - openstack-python3-train-jobs
+      - openstack-python3-ussuri-jobs
       - openstackclient-plugin-jobs
       - publish-openstack-docs-pti
       - release-notes-jobs-python3

playbooks/legacy/senlinclient-dsvm-functional/run.yaml

@@ -31,6 +31,7 @@
           [[local|localrc]]
           enable_plugin senlin https://opendev.org/openstack/senlin
           enable_service sl-api sl-eng
+          USE_PYTHON3=True
 
           EOF
         executable: /bin/bash

releasenotes/notes/drop-py-2-7-cced38f13fd3b44c.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Python 2.7 support has been dropped. Last release of python-senlinclient
+    to support python 2.7 is OpenStack Train. The minimum version of Python now
+    supported by python-senlinclient is Python 3.6.

setup.cfg

@@ -13,8 +13,6 @@ classifier =
     License :: OSI Approved :: Apache Software License
     Operating System :: POSIX :: Linux
     Programming Language :: Python
-    Programming Language :: Python :: 2
-    Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7

tox.ini

@@ -1,9 +1,11 @@
 [tox]
-envlist = py27,py37,pep8,releasenotes
-minversion = 2.0
+envlist = py37,pep8,releasenotes
+minversion = 3.1.1
 skipsdist = True
+ignore_basepython_conflict = True
 
 [testenv]
+basepython = python3
 setenv = VIRTUAL_ENV={envdir}
          CLIENT_NAME=python-senlinclient
 usedevelop = True
@@ -18,12 +20,10 @@ commands =
 whitelist_externals = find
 
 [testenv:bandit]
-basepython = python3
 deps = -r{toxinidir}/test-requirements.txt
 commands = bandit -r senlinclient -x tests -n5 -ll
 
 [testenv:pep8]
-basepython = python3
 commands =
     flake8
     # Check that .po and .pot files are valid:
@@ -31,7 +31,6 @@ commands =
 whitelist_externals = bash
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:functional]
@@ -41,7 +40,6 @@ setenv =
 passenv = OS_*
 
 [testenv:cover]
-basepython = python3
 setenv =
     PYTHON=coverage run --source senlinclient --parallel-mode
 commands =
@@ -52,11 +50,9 @@ commands =
     coverage report
 
 [testenv:debug]
-basepython = python3
 commands = oslo_debug_helper -t senlinclient/tests {posargs}
 
 [testenv:docs]
-basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/requirements.txt
@@ -64,7 +60,6 @@ deps =
 commands = sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:releasenotes]
-basepython = python3
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/requirements.txt
@@ -82,7 +77,6 @@ max-complexity=20
 import_exceptions = senlinclient.common.i18n
 
 [testenv:lower-constraints]
-basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt