HDFS-5748. Too much information shown in the dfs health page. Contributed by Haohui Mai

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1560215 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5434. Change block placement policy constructors from package private to protected. (Buddy Taylor via Arpit Agarwal)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1560217 13f79535-47bb-0310-9956-ffa450edef68
Move HADOOP-10143 to 2.4 section of CHANGES.txt

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1560222 13f79535-47bb-0310-9956-ffa450edef68