HDFS-5612: stub FSPermissionChecker handling of ACLs.
HDFS-5612: implement ACL enforcement logic.
HDFS-5612: begin testing FSPermissionChecker.
Merge branch 'HDFS-4685' into HDFS-5612
HDFS-5612: more tests.
HDFS-5612: small code cleanup.
HDFS-5612: remove unused import.
HDFS-5612: additional tests and clean up some permission bits in all tests.
HDFS-5612: add tests for permission denied on traversal.
HDFS-5612: clean up comments.
HDFS-5612: add comment to test class.
HDFS-5612: remove unused import in FSPermissionChecker.
Merge branch 'HDFS-4685' into HDFS-5612
HDFS-5612: correct comment on FSPermissionChecker#checkAcl in reaction to recent changes on HDFS-5673 patch.
HDFS-5612: refactor common test helpers to AclTestHelpers.
HDFS-5612: merge HDFS-4685 to HDFS-5612 with manual resolution of conflict for HDFS-5715 snapshot ID patch.
Merge branch 'HDFS-4685' into HDFS-5612
HDFS-5612: updates in reaction to latest HDFS-5758 patch.
HDFS-5612: update comments.
HDFS-5612: simplify by consolidating some conditional checks.