Make log message more descriptive to aid in debugging

streaming/src/main/scala/spark/streaming/Checkpoint.scala

@@ -100,8 +100,10 @@ class CheckpointWriter(checkpointDir: String) extends Logging {
       stopped = true
     }
     executor.shutdown()
+    val startTime = System.currentTimeMillis()
     val terminated = executor.awaitTermination(10, java.util.concurrent.TimeUnit.SECONDS)
-    logInfo("CheckpointWriter executor terminated ? " + terminated)
+    val endTime = System.currentTimeMillis()
+    logInfo("CheckpointWriter executor terminated ? " + terminated + ", waited for " + (endTime - startTime) + " ms.")
   }
 }