Forgotten config DS changes when no clustered topology owner

When there is no Owner for topology-manager entity, changes in config topology-netconf are not processed. When new owner appears, it does not examine state of topology-netconf. That means some user-configured connections are never opened, and some user-deconfigured connections are never torn down.

As lack of owner is not visible in Restconf output, current users can never be sure whether their changes will ever be applied.

Similar behavior was present in Openflowplugin project for Forwarding Rules Manager (FRM). They created FRS, S meaning Synchronize.

For Netconf, I recommend to add synchronization ability directly to odl-netconf-clustered_topology.
And possibly odl-netconf-topology as well, in order to re-establish previously configured connections after reboot in single node scenario.