[JENKINS-16824] log who's interrupting executors.

This bug indicates that people are having trouble understanding who's
responsible for aborting the build. This change records that
information through the logger.

core/src/main/java/hudson/model/Executor.java

@@ -49,6 +49,7 @@ import org.kohsuke.stapler.export.Exported;
 import javax.servlet.ServletException;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Vector;
 import java.util.logging.Logger;
@@ -135,6 +136,9 @@ public class Executor extends Thread implements ModelObject {
      * Interrupt the execution. Mark the cause and the status accordingly.
      */
     public void interrupt(Result result, CauseOfInterruption... causes) {
+        if (LOGGER.isLoggable(FINE))
+            LOGGER.log(FINE, String.format("%s is interrupted(%s): %s", getDisplayName(), result, Util.join(Arrays.asList(causes),",")), new InterruptedException());
+
         interruptStatus = result;
         synchronized (this.causes) {
             for (CauseOfInterruption c : causes) {