ModifiedNodeDoesNotExistException: floating-ip-info/router-ports/router-ports.../ports/ports...port-name=e21f56c9-1513-4753-bf40-f9d391c45658}] does not exist

Closing this issue as there is no report of re-occurrence of this exception https://git.opendaylight.org/gerrit/#/c/64930/

https://git.opendaylight.org/gerrit/#/c/64930/

Still in queens jobs: https://logs.opendaylight.org/releng/jenkins092/netvirt-csit-1node-openstack-queens-upstream-stateful-nitrogen/72/odl1_karaf.log.gz

Still seen in queens: https://logs.opendaylight.org/releng/jenkins092/netvirt-csit-1node-openstack-queens-upstream-stateful-nitrogen/58/odl1_err_warn_exception.log.gz

This exception occurrence might be due to concurrent deletion of floating-ip-info DS from

1) NeutronPortChangeListener(nvpnManager.dissociatefixedIPFromFloatingIP())
2) NeutronFloatingToFixedIpMappingChangeListener(update()->clearFloatingIpInfo)

when an attempt to delete VM instance(openstack server delete) is done without disassociating the neutron port from flaoting-ip port.

TODO: to explore if we need to use DJC in this case.