BUG 3548 - LLDP speaker doesn't start send LLDP packet on port up.

BUG 3548 - LLDP speaker doesn't start send LLDP packet on port up.

Listener on changes on changes on State subtree was added.

If instance of FlowCapableNodeConnector with port down is received
in NodeConnectorInventoryEventTranslator then it is stored to local map.
When event port up event is received then stored instance is looked up
in map, state part is replaced (with port up information) and it is sent
to LLDP.

Change-Id: Ic989a88c06b2e266c63375bd19e3ed2c2b4d4c2d
Signed-off-by: Jozef Gloncak <jgloncak@cisco.com>