Workaround py36 encoding pip bug

* ensures we add LC_ALL with UTF8 if not already set
* consolidate tox.ini indentation
* expose only generic py env on envlist
* sort envvars in tox

Change-Id: I3d01c5a19500db9a830c78193f82175b4c1d4361
Related: https://review.opendev.org/c/openstack/openstack-zuul-jobs/+/804890/

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 3.18.0
-envlist = pep8,py37,py36
+envlist = pep8,py
 skipsdist = True
 
 # Automatic envs (pyXX) will only use the python version appropriate to that
@@ -13,17 +13,19 @@ basepython = python3
 usedevelop = True
 install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master} {opts} {packages}
 passenv =
+  LANG
+  LANGUAGE
+  LC_*
   TERM
 setenv =
-   VIRTUAL_ENV={envdir}
-   LANG=en_US.UTF-8
-   LANGUAGE=en_US:en
-   LC_ALL=C
-   HOME={envdir}
+  HOME={envdir}
+  # https://github.com/pypa/pip/issues/10219#issuecomment-900898020
+  LC_ALL={env:LC_ALL:en_US.UTF-8}
+  VIRTUAL_ENV={envdir}
 deps =
-       -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
-       -r{toxinidir}/requirements.txt
-       -r{toxinidir}/test-requirements.txt
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -r{toxinidir}/requirements.txt
+  -r{toxinidir}/test-requirements.txt
 commands = stestr run {posargs}
 
 [testenv:bindep]
@@ -56,8 +58,8 @@ commands =
 
 [testenv:debug]
 deps =
-    oslotest
-    {[testenv]deps}
+  oslotest
+  {[testenv]deps}
 commands = oslo_debug_helper -t tripleoclient/tests {posargs}
 
 [testenv:docs]
@@ -79,11 +81,11 @@ commands =
 
 [testenv:genconfig]
 setenv =
-   HOME={env:HOME:/home/stack}
+  HOME={env:HOME:/home/stack}
 commands =
-   oslo-config-generator --config-file config-generator/undercloud.conf
-   oslo-config-generator --config-file config-generator/standalone.conf
-   oslo-config-generator --config-file config-generator/minion.conf
+  oslo-config-generator --config-file config-generator/undercloud.conf
+  oslo-config-generator --config-file config-generator/standalone.conf
+  oslo-config-generator --config-file config-generator/minion.conf
 
 [testenv:releasenotes]
 deps =