Add CHANGES.txt for HDFS-4953

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-4949@1515907 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -120,6 +120,9 @@ Trunk (Unreleased)
     HDFS-5004. Add additional JMX bean for NameNode status data
     (Trevor Lorimer via cos)
 
+    HDFS-4953. Enable HDFS local reads via mmap.
+    (Colin Patrick McCabe via wang).
+
   OPTIMIZATIONS
 
   BUG FIXES