Do not send PORT_UP notifications when the ports are cleared from the maintenance queue.

src/main/java/net/floodlightcontroller/linkdiscovery/internal/LinkDiscoveryManager.java

@@ -440,7 +440,6 @@ IFloodlightModule, IInfoProvider, IHAListener {
             NodePortTuple npt;
             npt = maintenanceQueue.remove();
             sendDiscoveryMessage(npt.getNodeId(), npt.getPortId(), false, false);
-            nptList.add(npt);
             count++;
         }