Stop testing python2.7

Train was the last release supporting python2. Let's rip the bandaid
off.

Change-Id: Id5424c420070b39b71e4163bbd5a471a2a94cb9e

.zuul.yaml

@@ -34,11 +34,9 @@
     name: shade-tox-tips
     check:
       jobs:
-        - shade-tox-py27-tips
         - shade-tox-py35-tips
     gate:
       jobs:
-        - shade-tox-py27-tips
         - shade-tox-py35-tips
 
 - job:

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 +1,10 @@
 [tox]
 minversion = 2.0
-envlist = py27,py37,pep8
+envlist = py37,pep8
 skipsdist = True
 
 [testenv]
+basepython = python3
 usedevelop = True
 passenv = UPPER_CONSTRAINTS_FILE
 install_command = pip install -U {opts} {packages}
@@ -26,7 +27,6 @@ commands = stestr --test-path ./shade/tests/functional run --serial {posargs}
            stestr slowest
 
 [testenv:pep8]
-basepython = python3
 usedevelop = False
 skip_install = True
 deps =
@@ -39,18 +39,15 @@ commands =
     flake8 shade
 
 [testenv:venv]
-basepython = python3
 commands = {posargs}
 
 [testenv:debug]
-basepython = python3
 whitelist_externals = find
 commands =
     find . -type f -name "*.pyc" -delete
     oslo_debug_helper {posargs}
 
 [testenv:cover]
-basepython = python3
 setenv =
     {[testenv]setenv}
     PYTHON=coverage run --source shade --parallel-mode
@@ -61,7 +58,6 @@ commands =
     coverage xml -o cover/coverage.xml
 
 [testenv:ansible]
-basepython = python3
 # Need to pass some env vars for the Ansible playbooks
 passenv = HOME USER
 deps =
@@ -72,7 +68,6 @@ deps =
 commands = {toxinidir}/extras/run-ansible-tests.sh -e {envdir} {posargs}
 
 [testenv:docs]
-basepython = python3
 deps =
     -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
     -r{toxinidir}/requirements.txt
@@ -81,7 +76,6 @@ commands =
   sphinx-build -W -d doc/build/doctrees -b html doc/source/ doc/build/html
 
 [testenv:releasenotes]
-basepython = python3
 skip_install = True
 deps =
     -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
@@ -103,7 +97,6 @@ builtins = _
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build
 
 [testenv:lower-constraints]
-basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt