SEBA-381 Expose ONU reason in XOS modeling

Change-Id: I921a53df6ef5a083b137c5529ecce8143863ea95
diff --git a/xos/synchronizer/pull_steps/pull_onus.py b/xos/synchronizer/pull_steps/pull_onus.py
index 18f047c..4f66304 100644
--- a/xos/synchronizer/pull_steps/pull_onus.py
+++ b/xos/synchronizer/pull_steps/pull_onus.py
@@ -110,6 +110,7 @@
             model.admin_state = onu["admin_state"]
             model.oper_status = onu["oper_status"]
             model.connect_status = onu["connect_status"]
+            model.reason = onu["reason"]
             model.xos_managed = False
 
             model.pon_port = pon_port