Merge "fix tox python3 overrides"

tox.ini

@@ -4,7 +4,6 @@ minversion = 2.3
 skipsdist = True
 
 [testenv]
-basepython = python3
 install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt?h=stable/pike} {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
          OS_STDOUT_CAPTURE=1
@@ -14,6 +13,7 @@ deps = -r{toxinidir}/test-requirements.txt
 whitelist_externals = reno
 
 [testenv:linters]
+basepython = python3
 whitelist_externals = bash
 commands =
   bash -c "find {toxinidir}          \
@@ -32,6 +32,7 @@ commands =
         -c {toxinidir}/.yamllint"
 
 [testenv:pep8]
+basepython = python3
 usedevelop = False
 skip_install = True
 deps =
@@ -40,12 +41,15 @@ commands =
     pep8
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:flake8]
+basepython = python3
 description = Dummy environment to allow flake8 to be run in subdir tox
 
 [testenv:pylint]
+basepython = python3
 description = Dummy environment to allow pylint to be run in subdir tox
 
 [testenv:api-ref]
@@ -73,6 +77,7 @@ commands =
 whitelist_externals = rm
 
 [testenv:newnote]
+basepython = python3
 # Re-use the releasenotes venv
 envdir = {toxworkdir}/releasenotes
 deps = -r{toxinidir}/doc/requirements.txt