Fix functional test gate

The functional test gate seems to be broken.  The environment
variables are not being passed through.

Change-Id: Ied1f56877e4793c5e88e59d2afb7f1a5b3868560

tox.ini

@@ -17,6 +17,7 @@ commands = flake8
 
 [testenv:functional]
 setenv = OS_TEST_PATH=./functional/tests
+passenv = OS_*
 
 [testenv:venv]
 commands = {posargs}