HDFS-9003. ForkJoin thread pool leaks. Contributed by Kihwal Lee.

(cherry picked from commit de928d566a119f0b7fa5f171719642cd86be0af7)
(cherry picked from commit 1d56325a80cdac5820079ac04fa18a7e5126f8ef)

Conflicts:
	hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
(cherry picked from commit 879567d24a6e3b625f639a88137fb1654c54c18f)

Conflicts:
	hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
2 files changed