MAPREDUCE-5357 does a fileystem chown() operation. chown() is not valid unless you are superuser. if you a chown() to yourself is a NOP, that is why has not been detected in Hadoop testcases where user is running as itself. However, in distcp testcases run by Oozie which use test users/groups from UGI for minicluster it is failing because of this chown() either because the test user does not exist of because the current use does not have privileges to do a chown().
We should revert
MAPREDUCE-5357. Windows should handle this with some conditional logic used only when running in Windows.
Opening a new JIRA and not reverting directly because
MAPREDUCE-5357 went in 2.1.0-beta.