Adding release 2.6.1 to CHANGES.txt

(cherry picked from commit 7c796fd12ca5092d74e6cc7044f28496f9884983)

hadoop-yarn-project/CHANGES.txt

@@ -1667,6 +1667,18 @@ Release 2.7.0 - 2015-04-20
     YARN-3055. Fixed ResourceManager's DelegationTokenRenewer to not stop token
     renewal of applications part of a bigger workflow. (Daryn Sharp via vinodkv)
 
+Release 2.6.1 - UNRELEASED
+
+  INCOMPATIBLE CHANGES
+
+  NEW FEATURES
+
+  IMPROVEMENTS
+
+  OPTIMIZATIONS
+
+  BUG FIXES
+
 Release 2.6.0 - 2014-11-18
 
   INCOMPATIBLE CHANGES