Re-registering node proxy in JMX on a node reconnect. Fixes #5186

Author: barancev

java/server/src/org/openqa/grid/selenium/proxy/DefaultRemoteProxy.java

@@ -71,6 +71,7 @@ public DefaultRemoteProxy(RegistrationRequest request, GridRegistry registry) {
     unregisterDelay = config.unregisterIfStillDownAfter != null ? config.unregisterIfStillDownAfter : DEFAULT_UNREGISTER_DELAY;
     downPollingLimit = config.downPollingLimit != null ? config.downPollingLimit : DEFAULT_DOWN_POLLING_LIMIT;
 
+    new JMXHelper().unregister(this.getObjectName());
     new JMXHelper().register(this);
   }
 

java/server/src/org/openqa/selenium/remote/server/jmx/JMXHelper.java

@@ -41,8 +41,7 @@ public void unregister(ObjectName objectName) {
       MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
       try {
         mbs.unregisterMBean(objectName);
-      } catch (Throwable t) {
-        t.printStackTrace();
+      } catch (Throwable ignore) {
       }
     }
   }