thread leak when connecting/disconnecting ovs nodes in a loop

just do this in a loop:

ovs-vsctl set-manager ${ODL_IP} 6640
sleep 1;
ovs-vsctl del-manager
sleep 1;

each connection is generating some threads but they are not cleaned
up after the disconnection or after waiting for some period of time.

feature installed is odl-ovsdb-southbound-impl-rest