Updated CHANGES.txt to reflect hadoop-2.6.0 release dates.

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

@@ -417,7 +417,7 @@ Release 2.7.0 - UNRELEASED
     HADOOP-11187 NameNode - KMS communication fails after a long period of
     inactivity. (Arun Suresh via atm)
 
-Release 2.6.0 - UNRELEASED
+Release 2.6.0 - 2014-11-15
 
   INCOMPATIBLE CHANGES
 

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

@@ -407,7 +407,7 @@ Release 2.7.0 - UNRELEASED
     HDFS-7366. BlockInfo should take replication as an short in the constructor.
     (Li Lu via wheat9)
 
-Release 2.6.0 - UNRELEASED
+Release 2.6.0 - 2014-11-15
 
   INCOMPATIBLE CHANGES
 

hadoop-mapreduce-project/CHANGES.txt

@@ -236,7 +236,7 @@ Release 2.7.0 - UNRELEASED
 
   BUG FIXES
 
-Release 2.6.0 - UNRELEASED
+Release 2.6.0 - 2014-11-15
 
   INCOMPATIBLE CHANGES
 

hadoop-yarn-project/CHANGES.txt

@@ -72,7 +72,7 @@ Release 2.7.0 - UNRELEASED
     YARN-2713. "RM Home" link in NM should point to one of the RMs in an 
     HA setup. (kasha)
 
-Release 2.6.0 - UNRELEASED
+Release 2.6.0 - 2014-11-15
 
   INCOMPATIBLE CHANGES