HADOOP-11105. Update CHANGES.txt.

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -831,6 +831,9 @@ Release 2.6.0 - UNRELEASED
 
     HADOOP-11099. KMS return HTTP UNAUTHORIZED 401 on ACL failure. (tucu)
 
+    HADOOP-11105. MetricsSystemImpl could leak memory in registered callbacks.
+    (Chuan Liu via cnauroth)
+
 Release 2.5.1 - 2014-09-05
 
   INCOMPATIBLE CHANGES