Drop python 2.7 support

We no longer support python 2.7 past Train.
Let's stop testings with python 2.7 and drop python 2.7 stuffs.

pypy in tox.ini is also dropped too. It is not used for long.

Change-Id: I8a07c007a129cd2141085a1a3cc7f81658c42db2

.zuul.yaml

@@ -2,7 +2,6 @@
     templates:
       - openstack-cover-jobs
       - openstack-lower-constraints-jobs
-      - openstack-python-jobs
       - openstack-python3-ussuri-jobs
       - publish-openstack-docs-pti
       - check-requirements

releasenotes/notes/drop-python-2.7-f615ebae463b2143.yaml

@@ -0,0 +1,5 @@
+---
+upgrade:
+  - |
+    Python 2.7 support has been dropped. The minimum version of Python now
+    supported by python-neutronclient is Python 3.6.

setup.cfg

@@ -14,8 +14,6 @@ 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
@@ -457,9 +455,6 @@ neutron.cli.v2 =
     vpn-ikepolicy-update = neutronclient.neutron.v2_0.vpn.ikepolicy:UpdateIKEPolicy
     vpn-ikepolicy-delete = neutronclient.neutron.v2_0.vpn.ikepolicy:DeleteIKEPolicy
 
-[wheel]
-universal = 1
-
 [extract_messages]
 keywords = _ gettext ngettext l_ lazy_gettext
 mapping_file = babel.cfg

tox.ini

@@ -1,10 +1,11 @@
 [tox]
-# py3 first to avoid .testrepository incompatibility
-envlist = py37,py27,pypy,pep8
+envlist = py37,pep8
 minversion = 2.3.2
 skipsdist = True
+ignore_basepython_conflict = True
 
 [testenv]
+basepython = python3
 setenv = VIRTUAL_ENV={envdir}
          LANG=en_US.UTF-8
          LANGUAGE=en_US:en
@@ -25,24 +26,20 @@ commands = sh -c "find . -type d -name '.?*' -prune -o \
 whitelist_externals = sh
 
 [testenv:pep8]
-basepython = python3
 commands =
   flake8
   {[testenv:bandit]commands}
 distribute = false
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:functional]
-basepython = python3
 setenv =
   OS_TEST_PATH = ./neutronclient/tests/functional
   OS_NEUTRONCLIENT_EXEC_DIR = {envdir}/bin
 
 [testenv:cover]
-basepython = python3
 setenv =
     {[testenv]setenv}
     PYTHON=coverage run --source neutronclient --parallel-mode
@@ -54,12 +51,10 @@ commands =
     coverage report
 
 [testenv:docs]
-basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:pdf-docs]
-basepython = python3
 envdir = {toxworkdir}/docs
 deps = {[testenv:docs]deps}
 whitelist_externals =
@@ -69,7 +64,6 @@ commands =
   make -C doc/build/pdf
 
 [testenv:releasenotes]
-basepython = python3
 deps = -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -a -E -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
@@ -82,13 +76,11 @@ import-order-style = pep8
 enable-extensions=H904
 
 [testenv:bandit]
-basepython = python3
 # B303: blacklist calls: md5, sha1
 deps = -r{toxinidir}/test-requirements.txt
 commands = bandit -r neutronclient -x tests -n5 -s B303
 
 [testenv:lower-constraints]
-basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt