Update the Netconf custom rpc as follows:
1) Create a message/field YANG reference.  This is used to keep the
XML tags in the same order as the fields appear in the YANG schema.
This applies only for custom RPCs (one of Netconf twist)
2) Annotate the proto RPCs with custom annotations which are used
when constructing an XML response

Change-Id: I07a8a3f2a44b7081c78e00dab05734a7c6b0a358
diff --git a/netconf/nc_rpc/ext/voltha_rpc.py b/netconf/nc_rpc/ext/voltha_rpc.py
index 37ba305..835f900 100644
--- a/netconf/nc_rpc/ext/voltha_rpc.py
+++ b/netconf/nc_rpc/ext/voltha_rpc.py
@@ -48,7 +48,7 @@
                  request=self.request)
 
         # Execute the request
-        res_dict = yield self.grpc_client.invoke_voltha_rpc(
+        res_dict, yang_options = yield self.grpc_client.invoke_voltha_rpc(
             service=self.service,
             method=self.method,
             params=self.request['params'],
@@ -62,7 +62,7 @@
 
         # Build the yang response
         self.rpc_response.node = self.rpc_response.build_yang_response(
-            root_elem, self.request, custom_rpc=True)
+            root_elem, self.request, yang_options=yang_options, custom_rpc=True)
         self.rpc_response.is_error = False
 
         returnValue(self.rpc_response)