TEP is part of old and new TZ when tz is updated after del-manager

TEP is part of two zones i.e. old transport zone and new transport zone when zone is removed after del-manager.

Ideally, it should get removed from old TZ when manager is connected back and new TZ is added from NB.

Steps:
1. Make sure setup is up with TZB transport-zone and tunnels
2. now execute "ovs-vsctl del-manager" in any of the ovs.
3. remove transport zone TZB from ovsdb and create new TZC
ovs-vsctl remove O . external_ids transport-zone
ovs-vsctl set O . external_ids:transport-zone=TZC
4. connect back manager to ODL.
sudo ovs-vsctl set-manager tcp:192.168.40.28:6640
5. check /restconf/operational/itm:not-hosted-transport-zones/ and create a TZC from NB
curl -X POST -H "Content-Type:application/json" -d @itm_tzc http://localhost:8181/restconf/config/itm:transport-zones