Adding release 2.7.2 to CHANGES.txt.

(cherry picked from commit aad6a7d5dba5858d6e9845f18c4baec16c91911d)

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

@@ -1,5 +1,17 @@
 Hadoop Change Log
 
+Release 2.7.2 - UNRELEASED
+
+  INCOMPATIBLE CHANGES
+
+  NEW FEATURES
+
+  IMPROVEMENTS
+
+  OPTIMIZATIONS
+
+  BUG FIXES
+
 Release 2.7.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -1,3 +1,17 @@
+Hadoop HDFS Change Log
+
+Release 2.7.2 - UNRELEASED
+
+  INCOMPATIBLE CHANGES
+
+  NEW FEATURES
+
+  IMPROVEMENTS
+
+  OPTIMIZATIONS
+
+  BUG FIXES
+
 Release 2.7.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-mapreduce-project/CHANGES.txt

@@ -1,5 +1,17 @@
 Hadoop MapReduce Change Log
 
+Release 2.7.2 - UNRELEASED
+
+  INCOMPATIBLE CHANGES
+
+  NEW FEATURES
+
+  IMPROVEMENTS
+
+  OPTIMIZATIONS
+
+  BUG FIXES
+
 Release 2.7.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-yarn-project/CHANGES.txt

@@ -1,5 +1,17 @@
 Hadoop YARN Change Log
 
+Release 2.7.2 - UNRELEASED
+
+  INCOMPATIBLE CHANGES
+
+  NEW FEATURES
+
+  IMPROVEMENTS
+
+  OPTIMIZATIONS
+
+  BUG FIXES
+
 Release 2.7.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES