Remove system scope token usage

Designate (like any other services) does not support the system
scope and now we are enabling the new defaults by default

- https://review.opendev.org/c/openstack/designate/+/925627

To enable the new defaults, we need to remove the usage of system
scope token from tests otherwise they fails

- https://review.opendev.org/c/openstack/designate/+/926446/

Needed-By: https://review.opendev.org/c/openstack/designate/+/925627
Needed-By: https://review.opendev.org/c/openstack/requirements/+/925464
Change-Id: I8162819f35e7aba5f9c5fab77f0308faf73287ea
diff --git a/designate_tempest_plugin/tests/base.py b/designate_tempest_plugin/tests/base.py
index 26f1f03..7a34419 100644
--- a/designate_tempest_plugin/tests/base.py
+++ b/designate_tempest_plugin/tests/base.py
@@ -68,8 +68,7 @@
     # can test for allowed and disallowed RBAC policies.
     credentials = ['admin', 'primary', 'alt']
     if CONF.dns_feature_enabled.enforce_new_defaults:
-        credentials.extend(['system_admin', 'system_reader',
-                            'project_member', 'project_reader'])
+        credentials.extend(['project_member', 'project_reader'])
 
     # A tuple of credentials that will be allocated by tempest using the
     # 'credentials' list above. These are used to build RBAC test lists.