[SEBA-723] Removing ONOS parameters from vOLT Service

Change-Id: I18a44dace5aa7b7c26f06d0b320631cc23114b71
diff --git a/xos/synchronizer/helpers.py b/xos/synchronizer/helpers.py
index cb310af..ade07e0 100644
--- a/xos/synchronizer/helpers.py
+++ b/xos/synchronizer/helpers.py
@@ -31,11 +31,20 @@
 
     @staticmethod
     def get_onos_voltha_info(olt_service):
+
+        # get the onos_fabric service
+        onos = [s.leaf_model for s in olt_service.provider_services if "onos" in s.name.lower()]
+
+        if len(onos) == 0:
+            raise Exception('Cannot find ONOS service in provider_services of vOLTService')
+
+        onos = onos[0]
+
         return {
-            'url': Helpers.format_url(olt_service.onos_voltha_url),
-            'port': olt_service.onos_voltha_port,
-            'user': olt_service.onos_voltha_user,
-            'pass': olt_service.onos_voltha_pass
+            'url': Helpers.format_url(onos.rest_hostname),
+            'port': onos.rest_port,
+            'user': onos.rest_username,
+            'pass': onos.rest_password
         }
 
     @staticmethod