Make user role logging optional

Not in every cloud does tempest have permissions to list the
role assignments. Since it is not critial for running the tests,
the logging of the user roles should be configurable.

Change-Id: I8aea2b597b9dd9bbdc5a1527fae03e86364aab4c
diff --git a/octavia_tempest_plugin/tests/test_base.py b/octavia_tempest_plugin/tests/test_base.py
index 5592571..f0477f4 100644
--- a/octavia_tempest_plugin/tests/test_base.py
+++ b/octavia_tempest_plugin/tests/test_base.py
@@ -136,6 +136,9 @@
         cls.set_network_resources()
         super(LoadBalancerBaseTest, cls).setup_credentials()
 
+        if not CONF.load_balancer.log_user_roles:
+            return
+
         # Log the user roles for this test run
         role_name_cache = {}
         for cred in cls.credentials: