update release date for release 4.1.0

git-svn-id: https://svn.apache.org/repos/asf/zookeeper/bookkeeper/branches/branch-4.1@1347636 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/CHANGES.txt b/CHANGES.txt
index 9422712..8de8dab 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,4 @@
-Release 4.1.0 - 2012-05-31
+Release 4.1.0 - 2012-06-07
 
   Non-backward compatible changes: