NullPointerException while deleting the interface from router.

NetVirt throws following null pointer exception when subnet interface is deleted from the router.

2016-05-17 00:14:09,886 | ERROR | ntDispatcherImpl | EventDispatcher | 300 - org.opendaylight.netvirt.openstack.net-virt - 1.3.0.SNAPSHOT | Exception in dispatching event NorthboundEvent [handler=NEUTRON_PORT, action=DELETE, port=NeutronPort [portUUID=4066b3ea-463d-4ea1-8707-3c79e435ab43, networkUUID=b1b2becb-fd1c-49fe-bf7d-a2e031d3697b, name=, adminStateUp=true, status=ACTIVE, macAddress=FA:16:3E:1C:65:BB, fixedIPs=[Neutron_IPs

], deviceID=ddbcf2ea-4562-43e6-a32b-838529afab10, deviceOwner=network:router_interface, tenantID=d95c67e9dbc44002b9ea0d947e4deb83, securityGroups=[], bindinghostID=, bindingvnicType=normal, bindingvnicType=normal, portSecurityEnabled=null], subnet=null, router=null, routerInterface=null, floatingIP=null, network=null, loadBalancer=null, loadBalancerPool=null, loadBalancerPoolMember=null, neutronsecurityRule=null]
java.lang.NullPointerException
at org.opendaylight.netvirt.openstack.netvirt.impl.NeutronL3Adapter.cleanupFloatingIPRules(NeutronL3Adapter.java:1466)[300:org.opendaylight.netvirt.openstack.net-virt:1.3.0.SNAPSHOT]
at org.opendaylight.netvirt.openstack.netvirt.impl.NeutronL3Adapter.handleNeutronPortEvent(NeutronL3Adapter.java:444)[300:org.opendaylight.netvirt.openstack.net-virt:1.3.0.SNAPSHOT]
at org.opendaylight.netvirt.openstack.netvirt.PortHandler.doNeutronPortDeleted(PortHandler.java:127)[300:org.opendaylight.netvirt.openstack.net-virt:1.3.0.SNAPSHOT]
at org.opendaylight.netvirt.openstack.netvirt.PortHandler.processEvent(PortHandler.java:169)[300:org.opendaylight.netvirt.openstack.net-virt:1.3.0.SNAPSHOT]
at org.opendaylight.netvirt.openstack.netvirt.impl.EventDispatcherImpl.dispatchEvent(EventDispatcherImpl.java:95)[300:org.opendaylight.netvirt.openstack.net-virt:1.3.0.SNAPSHOT]
at org.opendaylight.netvirt.openstack.netvirt.impl.EventDispatcherImpl.access$200(EventDispatcherImpl.java:27)[300:org.opendaylight.netvirt.openstack.net-virt:1.3.0.SNAPSHOT]
at org.opendaylight.netvirt.openstack.netvirt.impl.EventDispatcherImpl$1.run(EventDispatcherImpl.java:56)[300:org.opendaylight.netvirt.openstack.net-virt:1.3.0.SNAPSHOT]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)[:1.8.0_91]
at java.util.concurrent.FutureTask.run(FutureTask.java:266)[:1.8.0_91]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)[:1.8.0_91]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)[:1.8.0_91]
at java.lang.Thread.run(Thread.java:745)[:1.8.0_91]

This actually causes delay in the flow removal and packet leaks across the subnets even after subnet interface is removed from the router. Above issue can be recreated using following steps (please enable L3)

(1) Create two network/subnet (SB1, SB2) and spawn one VM in each network (VM1, VM2)
(2) Create router
(3) Attach both the network to router
(4) Ping from VM1 to VM2, ping will be successful.
(5) Now keep the ping on from VM1 to VM2
(6) Remove the interface of subnet SB2 from router
(7) You will see ping between VM1 and VM2 is still going on, ideally it should stop immediately. It will stop after a minute or so.
(8) If you look at the karaf log, you can see the NPE exception mentioned above.

Karaf log is attached with the mail.