fix tox python3 overrides

We want to default to running all tox environments under python 3, so
set the basepython value in each environment.

We do not want to specify a minor version number, because we do not
want to have to update the file every time we upgrade python.

We do not want to set the override once in testenv, because that
breaks the more specific versions used in default environments like
py35 and py36.

Change-Id: I0980a08f35965292a705ad7299cfdc9a433dfc87
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

tox.ini

@@ -4,7 +4,6 @@ envlist = py35,py27,pep8
 skipsdist = True
 
 [testenv]
-basepython = python3
 usedevelop = True
 install_command = pip install {opts} {packages}
 setenv =
@@ -20,11 +19,13 @@ commands = python setup.py testr --slowest --testr-args='{posargs}'
 basepython = python2.7
 
 [testenv:pep8]
+basepython = python3
 commands =
   flake8
   bandit -r castellan -x tests -s B105,B106,B107,B607
 
 [testenv:bandit]
+basepython = python3
 # This command runs the bandit security linter against the castellan
 # codebase minus the tests directory. Some tests are being excluded to
 # reduce the number of positives before a team inspection, and to ensure a
@@ -37,20 +38,25 @@ commands =
   bandit -r castellan -x tests -s B105,B106,B107,B607
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}
 
 [testenv:debug]
+basepython = python3
 commands = oslo_debug_helper {posargs}
 
 [testenv:cover]
+basepython = python3
 commands =
    python setup.py testr --coverage --testr-args='{posargs}'
    coverage report
 
 [testenv:docs]
+basepython = python3
 commands = python setup.py build_sphinx
 
 [testenv:releasenotes]
+basepython = python3
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:functional]
@@ -72,6 +78,7 @@ commands =
     {toxinidir}/tools/setup-vault-env.sh pifpaf -e VAULT_TEST run vault -- python setup.py testr --slowest --testr-args='{posargs}'
 
 [testenv:genconfig]
+basepython = python3
 commands =
     oslo-config-generator --config-file=etc/castellan/functional-config-generator.conf
     oslo-config-generator --config-file=etc/castellan/sample-config-generator.conf
@@ -87,6 +94,7 @@ enable-extensions = H106,H203
 import_exceptions = castellan.i18n
 
 [testenv:lower-constraints]
+basepython = python3
 deps =
   -c{toxinidir}/lower-constraints.txt
   -r{toxinidir}/test-requirements.txt