Fix for AMQ-5652: IdGenerator not optimal in port restricted environments.

We now support configuring via system props activemq.idgenerator.hostname and activemq.idgenerator.localport which are used as the base part of GUIDs.

activemq-client/src/main/java/org/apache/activemq/util/IdGenerator.java

@@ -59,7 +59,7 @@ public class IdGenerator {
             int idGeneratorPort = 0;
             ServerSocket ss = null;
             try {
-                if( hostName!=null ) {
+                if( hostName==null ) {
                     hostName = InetAddressUtil.getLocalHostName();
                 }
                 if( localPort==0 ) {