Revert "CHANGES.txt: add YARN-2977"

This reverts commit 3419091631777ec04dd1a9e2bf24adab2496c5ce.

hadoop-yarn-project/CHANGES.txt

@@ -1,20 +1,5 @@
 Hadoop YARN Change Log
 
-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