[SPARK-20875] Spark should print the log when the directory has been deleted

[https://issues.apache.org/jira/browse/SPARK-20875](https://issues.apache.org/jira/browse/SPARK-20875)
When the "deleteRecursively" method is invoked,spark doesn't print any log if the path was deleted.For example,spark only print "Removing directory" when the worker began cleaning spark.work.dir,but didn't print any log about "the path has been delete".So, I can't judge whether the path was deleted form the worker's logfile,If there is any accidents about Linux.

Author: liuzhaokun <liu.zhaokun@zte.com.cn>

Closes #18102 from liu-zhaokun/master_log.