lets wait a little for the background thread to shut first so that threads tend to shut down nicely

git-svn-id: https://svn.apache.org/repos/asf/incubator/activemq/trunk@428419 13f79535-47bb-0310-9956-ffa450edef68

activemq-core/src/main/java/org/apache/activemq/broker/TransportStatusDetector.java

@@ -112,5 +112,8 @@ public class TransportStatusDetector implements Service,Runnable{
     }
     public void stop() throws Exception{
         started.set(false);
+        if (runner != null) {
+            runner.join(getSweepInterval() * 5);
+        }
     }
 }