Fix CHANGES.txt to remove repeated sections for 2.3.0

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1518908 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -1,20 +1,5 @@
 Hadoop HDFS Change Log
 
-Release 2.3.0 - UNRELEASED
-
-  INCOMPATIBLE CHANGES
-
-  NEW FEATURES
-
-  IMPROVEMENTS
-
-    HDFS-5144. Document time unit to NameNodeMetrics. (Akira Ajisaka via
-    suresh)
-
-  OPTIMIZATIONS
-
-  BUG FIXES
-
 Release 2.3.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES
@@ -41,6 +26,9 @@ Release 2.3.0 - UNRELEASED
 
     HDFS-4994. Audit log getContentSummary() calls. (Robert Parker via kihwal)
 
+    HDFS-5144. Document time unit to NameNodeMetrics. (Akira Ajisaka via
+    suresh)
+
   OPTIMIZATIONS
 
   BUG FIXES