OpenStack integration does not work in Helium SR3

Issue Scenario :

Network creation is getting failed in OpenStack integration with VTN as Network Provider

Reproduce the Bug:

First get a set-up for VTN Manager with controller using the example:
Install VTNManager to use VTN API(VTN Coordinator is not required):

https://wiki.opendaylight.org/view/Release/Helium/VTN/Installation_Guide.

After Controller is up then start stacking Openstack(Control Node) as in the below page:

https://wiki.opendaylight.org/view/Release/Helium/VTN/User_Guide/OpenStack_Support.

When Openstack is getting stacked, the network(OVS) creation is getting failed in the control node.

The Error message in the OpenStack log is:

2015-03-20 01:51:33.051 | [ERROR] /opt/stack/devstack/functions-common:534 Failure creating SUBNET_ID for eba3edb79f984e7392ff9551fcf0b487

The Error message in the ODL Controller is :

2015-03-20 01:51:25,997 | ERROR | -bio-8080-exec-7 | ContainerResponse | 165 - com.sun.jersey.jersey-server - 1.17.0 | Mapped exception to response: 503 (Service Unavailable)
org.opendaylight.controller.northbound.commons.exception.ServiceUnavailableException

Occurrence of the issue :

Occurs every time of integrating OpenStack with VTN