it not necessary to do `cleanupTempFiles` while ditcp commit job in direct mode, because it there is no temp files in direct mode.
This clean operation will increase the task execution time, because it will get the list of files in the target path. When the number of files in the target path is very large, this operation will be very slow.
note there are two patches which need to be cherrypicked when picking this up; the original patch and a followup, both with
HADOOP-18582 in the title