Addendum to CHANGES.txt for MR-6689

hadoop-mapreduce-project/CHANGES.txt

@@ -30,6 +30,9 @@ Release 2.6.5 - UNRELEASED
     MAPREDUCE-6302. Preempt reducers after a configurable timeout 
     irrespective of headroom. (kasha via wangda)
 
+    MAPREDUCE-6689. MapReduce job can infinitely increase number of reducer
+    resource requests (Wangda Tan via jlowe)
+
 Release 2.6.4 - 2016-02-11
 
   INCOMPATIBLE CHANGES