disabling the networkdiscovery did not really disable it

Author: jantje

io.sloeber.core/src/cc/arduino/packages/discoverers/NetworkDiscovery.java

@@ -107,7 +107,7 @@ public static void start() {
 	}
 
 	public static void stop() {
-		timer.purge();
+		timer.cancel();
 		// we don't close each JmDNS instance as it's too slow
 	}