HDFS-5908. Change AclFeature to capture list of ACL entries in an ImmutableList. Contributed by Chris Nauroth.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1572142 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5936. MiniDFSCluster does not clean data left behind by SecondaryNameNode. Contributed by Binglin Chang.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1572150 13f79535-47bb-0310-9956-ffa450edef68