SEBA-271 fix duplicate field number

Change-Id: Ie48d8c9ba3df395edc8fdf8fba56979c45f3d570
diff --git a/xos/synchronizer/models/att-workflow-driver.xproto b/xos/synchronizer/models/att-workflow-driver.xproto
index 5a24d8b..7216dff 100644
--- a/xos/synchronizer/models/att-workflow-driver.xproto
+++ b/xos/synchronizer/models/att-workflow-driver.xproto
@@ -25,5 +25,5 @@
     required manytoone owner->AttWorkflowDriverService:whitelist_entries = 1 [db_index = True, tosca_key=True];
     required string serial_number = 2 [max_length = 254, db_index = False, tosca_key=True, unique_with = "owner"];
     required int32 pon_port_id = 3 [db_index = False, help_text = "PON Port on which this ONU is expected to show up"];
-    required string device_id = 3 [max_length = 54, db_index = False, help_text = "OLT Device (logical device id) on which this ONU is expected to show up"];
+    required string device_id = 4 [max_length = 54, db_index = False, help_text = "OLT Device (logical device id) on which this ONU is expected to show up"];
 }