Merge "fix tox python3 overrides"

tox.ini

@@ -22,6 +22,7 @@ commands =
   stestr slowest
 
 [testenv:debug]
+basepython = python3
 commands = oslo_debug_helper -t manilaclient/tests {posargs}
 
 [testenv:debug-py27]
@@ -33,11 +34,13 @@ basepython = python3.5
 commands = oslo_debug_helper -t manilaclient/tests {posargs}
 
 [testenv:pep8]
+basepython = python3
 commands =
   python setup.py check --restructuredtext --strict
   flake8
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:docs]
@@ -52,6 +55,7 @@ commands =
   sphinx-build -b html doc/source doc/build/html
 
 [testenv:releasenotes]
+basepython = python3
 deps =
        -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
        -r{toxinidir}/requirements.txt
@@ -73,12 +77,14 @@ commands =
   stestr run '{posargs}'
 
 [testenv:genconfig]
+basepython = python3
 whitelist_externals = bash
 commands =
   {envdir}/bin/python setup.py install
   {envdir}/bin/oslo-config-generator --config-file etc/oslo-config-generator/manilaclient.conf
 
 [testenv:cover]
+basepython = python3
 setenv =
   {[testenv]setenv}
   PYTHON=coverage run --source manilaclient --parallel-mode