Merge "fix tox python3 overrides"

tox.ini

@@ -17,6 +17,7 @@ commands = find . -type f -name "*.py[c|o]" -delete
 whitelist_externals = find
 
 [testenv:debug]
+basepython = python3
 commands = oslo_debug_helper -t heatclient/tests {posargs}
 
 [testenv:debug-py27]
@@ -28,10 +29,12 @@ basepython = python3.5
 commands = oslo_debug_helper -t heatclient/tests {posargs}
 
 [testenv:pep8]
+basepython = python3
 commands =
     flake8
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:functional]
@@ -41,11 +44,13 @@ setenv =
 passenv = OS_*
 
 [testenv:cover]
+basepython = python3
 commands =
     python setup.py testr --coverage --testr-args='{posargs}'
     coverage report
 
 [testenv:docs]
+basepython = python3
 deps =
        -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
        -r{toxinidir}/doc/requirements.txt
@@ -60,6 +65,7 @@ max-complexity=20
 import_exceptions = heatclient._i18n
 
 [testenv:releasenotes]
+basepython = python3
 deps =
        -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
        -r{toxinidir}/doc/requirements.txt