Fix passenv declaration in tox.ini and function tests python env

While running the tests with the latest tox I was getting the following error message:
```
failed with pass_env values cannot contain whitespace, use comma to have multiple values in a single line'

```

That error is happening because of the passenv declaration. This patch is proposing a fix for that.

Besides the `tox` issue, we also needed to create a patch for the use of virtual env inside DevStack.
This patches presents a solution to run tests using the virtual env of DevStack.

Change-Id: Id8249ebb15d4047dcc6181908eae66eb39722863

.zuul.yaml

@@ -23,6 +23,7 @@
         CLOUDKITTY_FETCHER: keystone
         DEVSTACK_GATE_USE_PYTHON3: "True"
         USE_PYTHON3: True
+        GLOBAL_VENV: False
       devstack_services:
         ck-api: true
         horizon: false

cloudkittyclient/tests/functional/base.py

@@ -20,6 +20,10 @@ import subprocess
 
 from cloudkittyclient.tests import utils
 
+from oslo_log import log
+
+LOG = log.getLogger(__name__)
+
 
 class BaseFunctionalTest(utils.BaseTestCase):
 
@@ -27,8 +31,16 @@ class BaseFunctionalTest(utils.BaseTestCase):
              flags='', params='', fmt='-f json', stdin=None, has_output=True):
         if not has_output:
             fmt = ''
+
+        system_variables = os.environ.copy()
+        LOG.info("System variables [%s] found when executing the tests.",
+                 system_variables)
+
         cmd = ' '.join([executable, flags, action, params, fmt])
+
+        LOG.info("Command being executed: [%s].", cmd)
         cmd = shlex.split(cmd)
+
         p = subprocess.Popen(
             cmd, env=os.environ.copy(), shell=False,
             stdout=subprocess.PIPE, stderr=subprocess.PIPE,

tox.ini

@@ -9,6 +9,7 @@ basepython = python3
 usedevelop = True
 install_command = pip install -U {opts} {packages}
 setenv =
+   DEVSTACK_VENV={env:DEVSTACK_VENV}
    VIRTUAL_ENV={envdir}
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
@@ -29,12 +30,40 @@ commands =
 commands = oslo_debug_helper -t cloudkittyclient/tests {posargs}
 
 [testenv:functional-v1]
-passenv = OS_CLOUD OS_PROJECT_DOMAIN_ID OS_USER_DOMAIN_ID OS_PROJECT_DOMAIN_NAME OS_USER_DOMAIN_NAME OS_PROJECT_NAME OS_IDENTITY_API_VERSION OS_PASSWORD OS_AUTH_TYPE OS_AUTH_URL OS_USERNAME OS_ENDPOINT
+passenv =
+      OS_CLOUD
+      OS_PROJECT_DOMAIN_ID
+      OS_USER_DOMAIN_ID
+      OS_PROJECT_DOMAIN_NAME
+      OS_USER_DOMAIN_NAME
+      OS_PROJECT_NAME
+      OS_IDENTITY_API_VERSION
+      OS_PASSWORD
+      OS_AUTH_TYPE
+      OS_AUTH_URL
+      OS_USERNAME
+      OS_ENDPOINT
+      DEVSTACK_VENV
+      VIRTUAL_ENV
 setenv = OS_RATING_API_VERSION=1
 commands = stestr run --concurrency=1 --test-path ./cloudkittyclient/tests/functional/v1
 
 [testenv:functional-v2]
-passenv = OS_CLOUD OS_PROJECT_DOMAIN_ID OS_USER_DOMAIN_ID OS_PROJECT_DOMAIN_NAME OS_USER_DOMAIN_NAME OS_PROJECT_NAME OS_IDENTITY_API_VERSION OS_PASSWORD OS_AUTH_TYPE OS_AUTH_URL OS_USERNAME OS_ENDPOINT
+passenv = 
+      OS_CLOUD
+      OS_PROJECT_DOMAIN_ID
+      OS_USER_DOMAIN_ID
+      OS_PROJECT_DOMAIN_NAME
+      OS_USER_DOMAIN_NAME
+      OS_PROJECT_NAME
+      OS_IDENTITY_API_VERSION
+      OS_PASSWORD
+      OS_AUTH_TYPE
+      OS_AUTH_URL
+      OS_USERNAME
+      OS_ENDPOINT
+      DEVSTACK_VENV
+      VIRTUAL_ENV
 setenv = OS_RATING_API_VERSION=2
 commands = stestr run --concurrency=1 --test-path ./cloudkittyclient/tests/functional/v2