Update CHANGES.txt for WHIRR-751
diff --git a/CHANGES.txt b/CHANGES.txt
index 19ecd05..fc3207b 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -8,6 +8,8 @@
 
   IMPROVEMENTS
 
+    WHIRR-751. Improve Kerberos service (graham)
+
     WHIRR-748. Move to jclouds 1.6.2-incubating. (abayer)
     
     WHIRR-726. Allow specifying a Kerberos user other than