Pass creds into the clients.Manager() in functional tests

Because of some changes in tempest now it is nesessary to
set credentials to the client.Manager()

Change-Id: I37e95118064317797dc3277ce79b195a8ebd328b

mistral/tests/functional/base.py

@@ -20,6 +20,7 @@ import mock
 import six
 
 from tempest import clients
+from tempest.common import credentials_factory as creds
 from tempest import config
 from tempest import test as test
 from tempest_lib import auth
@@ -248,7 +249,10 @@ class TestCase(test.BaseTestCase):
             cls.mgr = mock.MagicMock()
             cls.mgr.auth_provider = AuthProv()
         else:
-            cls.mgr = clients.Manager()
+            cls.creds = creds.get_configured_credentials(
+                credential_type='user'
+            )
+            cls.mgr = clients.Manager(cls.creds)
 
         if cls._service == 'workflowv2':
             cls.client = MistralClientV2(