CHANGES.txt: add YARN-2977

hadoop-yarn-project/CHANGES.txt

@@ -256,6 +256,21 @@ Release 2.7.0 - UNRELEASED
     YARN-2952. Fixed incorrect version check in StateStore. (Rohith Sharmaks
     via jianhe)
 
+Release 2.6.1 - Unreleased
+
+  INCOMPATIBLE CHANGES
+
+  NEW FEATURES
+
+  IMPROVEMENTS
+
+  OPTIMIZATIONS
+
+  BUG FIXES
+
+    YARN-2977. Fixed intermittent TestNMClient failure.
+    (Junping Du via ozawa)
+
 Release 2.6.0 - 2014-11-18
 
   INCOMPATIBLE CHANGES