Update comment

Author: zsxwing

core/src/main/scala/org/apache/spark/scheduler/cluster/CoarseGrainedSchedulerBackend.scala

@@ -181,8 +181,7 @@ class CoarseGrainedSchedulerBackend(scheduler: TaskSchedulerImpl, val rpcEnv: Rp
       case RemoveExecutor(executorId, reason) =>
         // We will remove the executor's state and cannot restore it. However, the connection
         // between the driver and the executor may be still alive so that the executor won't exit
-        // automatically (E.g., Master will send RemoveExecutor when a work is lost but the executor
-        // is still alive), so try to tell the executor to stop itself. See SPARK-13519.
+        // automatically, so try to tell the executor to stop itself. See SPARK-13519.
         executorDataMap.get(executorId).foreach(_.executorEndpoint.send(StopExecutor))
         removeExecutor(executorId, reason)
         context.reply(true)