Create 3 sessions with 3 different node-ids from the controllers with an ovsdb instance.
Topology shard shows 3 entries.
Restart controller
Only 1 session is retained and the other 2 are not with the below warn
```2018-02-13 16:26:50,449 | WARN | on-dispatcher-62 | OvsdbDataTreeChangeListener | 414 - org.opendaylight.ovsdb.southbound-impl - 1.5.1 | Connection to device ConnectionInfo{getRemoteIp=IpAddress [_ipv4Address=Ipv4Address [_value=10.18.130.109]], getRemotePort=PortNumber [_value=6634], augmentations={}} already exists. Plugin does not allow multiple connections to same device, hence dropping the request OvsdbNodeAugmentation{getConnectionInfo=ConnectionInfo{getRemoteIp=IpAddress [_ipv4Address=Ipv4Address [_value=10.18.130.109]], getRemotePort=PortNumber [_value=6634], augmentations={}}}```
After the restart when we try to create new or existing node-id entries to the same instance the WARN is seen but it also allows the node entries to be created...