remove my years old comments (no content change)

doc/guide/kea-guide.xml

@@ -116,21 +116,3 @@
   <!-- <index>    <title>Index</title> </index> -->
 
 </book>
-
-<!--
-
-TODO:
-
-Overview
-
-Getting BIND 10 Installed
-  Basics
-  Dependencies
-  Optional
-  Advanced
-
-How Does Everything Work Together?
-
-Need Help?
-
--->