Do not generate bytecode in tests

This is a known best practise during development, to avoid leaving
stale bytecode after a file is deleted.

Change-Id: I556a4bc7c78ec870bed9ce503524869ac554b423
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

tox.ini

@@ -8,15 +8,14 @@ setenv =
   OS_STDOUT_CAPTURE=1
   OS_STDERR_CAPTURE=1
   OS_TEST_TIMEOUT=60
+  PYTHONDONTWRITEBYTECODE=1
 constraints =
   {env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
 deps =
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/test-requirements.txt
 commands =
-  find . -type f -name "*.pyc" -delete
   stestr run {posargs}
-allowlist_externals = find
 
 [testenv:pep8]
 skip_install = true
@@ -37,9 +36,10 @@ commands =
 
 [testenv:functional]
 setenv =
+  {[testenv]setenv}
   OS_TEST_PATH = ./tests/functional
-  ZAQARCLIENT_AUTH_FUNCTIONAL = 1
-  ZAQARCLIENT_TEST_FUNCTIONAL = 1
+  ZAQARCLIENT_AUTH_FUNCTIONAL=1
+  ZAQARCLIENT_TEST_FUNCTIONAL=1
 passenv =
   ZAQAR_SERVICE_HOST
   ZAQAR_ENDPOINT