Fix job result not being sent back to gearman client

This fixes a bug that causes the result object to be left off of the
returned data packet after a job finishes executing.  This only occurs
when the job request sets the node to temporary offline (i.e.
"OFFLINE_NODE_WHEN_COMPLETE":"true").  The problem is that the
ComputerListener.onTemporaryOffline event was stopping the
gearman worker which causes a disconnect to the gearman client thus
not being able to send back the results for the job.  The worker should
not stop on a temporary offline, only on disconnect and delete of a node.
The fix is to only re-register the gearman functions instead of stopping
the workers on a temporary online/offline of a node.

Change-Id: Icf672acf059d6cb0e16a6685d637824c678ea5be

src/main/java/hudson/plugins/gearman/ComputerListenerImpl.java

@@ -109,8 +109,8 @@ public class ComputerListenerImpl extends ComputerListener {
             return;
         }
 
-        // stop worker when jenkins slave is set to offline
-        GearmanProxy.getInstance().stop(c);
+        // re-register gearman functions on node status change,
+        GearmanProxy.getInstance().registerJobs();
     }
 
     @Override
@@ -123,16 +123,8 @@ public class ComputerListenerImpl extends ComputerListener {
             return;
         }
 
-        GearmanProxy gp = GearmanProxy.getInstance();
-        /*
-         * Spawn management executor worker if one doesn't exist yet.
-         * This worker does not need any executors. It only needs
-         * to work with gearman.
-         */
-        gp.createManagementWorker();
-
-        // on brining a slave back online
-        gp.createExecutorWorkersOnNode(c);
+        // re-register gearman functions on node status change,
+        GearmanProxy.getInstance().registerJobs();
     }
 
 }