Merge "tox: Drop redundant passenv"

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 envlist = py3,pep8
-minversion = 3.18.0
+minversion = 4.0.0
 ignore_basepython_conflict = True
 
 [testenv]
@@ -9,13 +9,6 @@ usedevelop = True
 setenv =
   PYTHONDONTWRITEBYTECODE = 1
   PYTHONWARNINGS=default::DeprecationWarning
-passenv =
-  http_proxy
-  HTTP_PROXY
-  https_proxy
-  HTTPS_PROXY
-  no_proxy
-  NO_PROXY
 deps =
     -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
     -r{toxinidir}/requirements.txt