HDFS-5849. Removing ACL from an inode fails if it has only a default ACL. Contributed by Chris Nauroth.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-4685@1563205 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10270. getfacl does not display effective permissions of masked. Contributed by Chris Nauroth.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-4685@1563219 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5614. NameNode: implement handling of ACLs in combination with snapshots. Contributed by Chris Nauroth.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-4685@1563304 13f79535-47bb-0310-9956-ffa450edef68
merge HDFS-4685 to HDFS-5858 with manual resolution
HDFS-5858: remove unneeded passing of snapshot ID