Merge pull request #1689 from deadmoose/patch-3

Remove erroneous '+ ' from log message.

core/src/main/java/jenkins/slaves/JnlpSlaveAgentProtocol.java

@@ -123,7 +123,7 @@ public class JnlpSlaveAgentProtocol extends AgentProtocol {
                         @Override
                         public void onClosed(Channel channel, IOException cause) {
                             if(cause!=null)
-                                LOGGER.log(Level.WARNING, Thread.currentThread().getName()+" for + " + nodeName + " terminated",cause);
+                                LOGGER.log(Level.WARNING, Thread.currentThread().getName() + " for " + nodeName + " terminated", cause);
                             try {
                                 socket.close();
                             } catch (IOException e) {