Host is not entering in to maintenance mode in ovsvapp agent-monitoring

I have two host(Host-A and Host-B) and each host having ovsvapp vm.
When one ovsvapp-agent is down in Host A, the tenant vm of Host -A is migrated to Host B but Host A ovsvapp is not powered off and Host A is not entered in to maintenance mode.

logs of ovsvapp-agent.log in ovavpp Host-B:

2015-11-18 07:05:48.671 ERROR networking_vsphere.agent.ovsvapp_agent [req-c240afe3-e21e-463a-ba97-4c6a3c194cfe None None] Unable to poweroff ovsvapp-172-21-10-33 OVSvApp VM.
2015-11-18 07:05:48.671 8386 TRACE networking_vsphere.agent.ovsvapp_agent Traceback (most recent call last):
2015-11-18 07:05:48.671 8386 TRACE networking_vsphere.agent.ovsvapp_agent File "/opt/stack/networking-vsphere/networking_vsphere/agent/ovsvapp_agent.py", line 1691, in device_update
2015-11-18 07:05:48.671 8386 TRACE networking_vsphere.agent.ovsvapp_agent self.net_mgr.get_driver().session, vm_mor)
2015-11-18 07:05:48.671 8386 TRACE networking_vsphere.agent.ovsvapp_agent File "/opt/stack/networking-vsphere/networking_vsphere/utils/resource_util.py", line 83, in set_vm_poweroff
2015-11-18 07:05:48.671 8386 TRACE networking_vsphere.agent.ovsvapp_agent raise Exception(e)
2015-11-18 07:05:48.671 8386 TRACE networking_vsphere.agent.ovsvapp_agent Exception: 'NoneType' object has no attribute 'state'
2015-11-18 07:05:48.671 8386 TRACE networking_vsphere.agent.ovsvapp_agent