Fix missing "raise" before cls.skipException

"raise" is missing before cls.skipException in
test_auto_allocated_topology_rbac.py, this is to fix it.

Change-Id: I8a516bcc2899a38e82f56d955f40364d5dd7929f
diff --git a/patrole_tempest_plugin/tests/api/network/test_auto_allocated_topology_rbac.py b/patrole_tempest_plugin/tests/api/network/test_auto_allocated_topology_rbac.py
index ed6a3f5..3db0616 100644
--- a/patrole_tempest_plugin/tests/api/network/test_auto_allocated_topology_rbac.py
+++ b/patrole_tempest_plugin/tests/api/network/test_auto_allocated_topology_rbac.py
@@ -54,7 +54,7 @@
 
         if len(ports) != expected_ports_count:
             msg = "Auto Allocated Topology in use."
-            cls.skipException(msg)
+            raise cls.skipException(msg)
 
     @decorators.idempotent_id('A0606AFE-065E-4C09-8E51-58EE7FBA30A2')
     @decorators.attr(type='slow')