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} {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
 #bashate ignore errors
 #E010: do not on the same line as for
@@ -33,6 +33,7 @@ commands =
             -print0 | xargs -0 yamllint"
 
 [testenv:pep8]
+basepython = python3
 usedevelop = False
 deps =
     flake8<3.6.0
@@ -71,6 +72,7 @@ commands =
 whitelist_externals = rm
 
 [testenv:newnote]
+basepython = python3
 # Re-use the releasenotes venv
 envdir = {toxworkdir}/releasenotes
 deps = -r{toxinidir}/doc/requirements.txt