Merge "fix tox python3 overrides"

tox.ini

@@ -19,6 +19,7 @@ whitelist_externals =
     find
 
 [testenv:tips]
+basepython = python3
 # tests what happens with unreleased version of dependencies, like jenkins-job-builder
 install_command = pip install -U {opts} {packages}
 commands =
@@ -28,6 +29,7 @@ commands =
     stestr run --slowest {posargs}
 
 [testenv:cover]
+basepython = python3
 setenv =
     {[testenv]setenv}
     PYTHON=coverage run --source jenkins --parallel-mode
@@ -38,12 +40,15 @@ commands =
     coverage xml -o cover/coverage.xml
 
 [testenv:pep8]
+basepython = python3
 commands = flake8
 
 [testenv:docs]
+basepython = python3
 commands = python setup.py build_sphinx
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [flake8]
@@ -56,6 +61,7 @@ show-source = True
 exclude = .venv,.tox,dist,doc,build,*.egg
 
 [testenv:bindep]
+basepython = python3
 # Do not install any requirements. We want this to be fast and work even if
 # system dependencies are missing, since it's used to tell you what system
 # dependencies are missing! This also means that bindep must be installed