Updated CHANGES.txt files to reflect the 2.0.0-alpha release

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1346151 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -69,7 +69,7 @@ Release 2.0.1-alpha - UNRELEASED
     HADOOP-8481. update BUILDING.txt to talk about cmake rather than autotools.
     (Colin Patrick McCabe via eli)
 
-Release 2.0.0-alpha - UNRELEASED
+Release 2.0.0-alpha - 05-23-2012
 
   INCOMPATIBLE CHANGES
 

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

@@ -153,7 +153,7 @@ Release 2.0.1-alpha - UNRELEASED
     HDFS-3501. Checkpointing with security enabled will stop working
     after ticket lifetime expires. (atm via eli)
 
-Release 2.0.0-alpha - UNRELEASED
+Release 2.0.0-alpha - 05-23-2012
 
   INCOMPATIBLE CHANGES
 

hadoop-mapreduce-project/CHANGES.txt

@@ -42,7 +42,7 @@ Release 2.0.1-alpha - UNRELEASED
     MAPREDUCE-4307. TeraInputFormat calls FileSystem.getDefaultBlockSize()
     without a Path - Failure when using ViewFileSystem. (Ahmed Radwan via eli)
 
-Release 2.0.0-alpha - UNRELEASED
+Release 2.0.0-alpha - 05-23-2012
 
   INCOMPATIBLE CHANGES