HDFS-7385. ThreadLocal used in FSEditLog class causes FSImage permission mess up. Contributed by jiangyu.

(cherry picked from commit b0a41de68c5b08f534ca231293de053c0b0cbd5d)
(cherry picked from commit 4e9001530f7bc414b43723858cf7984f707b30e0)
Preparing to release hadoop-2.6.0-rc1.

(cherry picked from commit 9ff7315cbe9804bebcd1ec093fac7828a72ddf59)

Conflicts:
	hadoop-common-project/hadoop-common/CHANGES.txt
	hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
	hadoop-mapreduce-project/CHANGES.txt
	hadoop-yarn-project/CHANGES.txt