Fixing status handling when ONU is disabled

Change-Id: Icf29df5fd8c3556d7d5f1d1d2d3b674796b0e25a
diff --git a/xos/synchronizer/model_policies/model_policy_att_workflow_driver_serviceinstance.py b/xos/synchronizer/model_policies/model_policy_att_workflow_driver_serviceinstance.py
index fb8a9d6..8513d41 100644
--- a/xos/synchronizer/model_policies/model_policy_att_workflow_driver_serviceinstance.py
+++ b/xos/synchronizer/model_policies/model_policy_att_workflow_driver_serviceinstance.py
@@ -44,6 +44,9 @@
             # we validate the ONU state only if it is enabled or awaiting,
             # if it's disabled it means someone has disabled it
             self.validate_onu_state(si)
+        else:
+            # just clean the status
+            si.status_message = ""
 
         # handling the subscriber status
         subscriber = self.get_subscriber(si.serial_number)