Add one TODO item for xfrin module, do zone transfer from notifyfrom. trivial skip review.

git-svn-id: svn://bind10.isc.org/svn/bind10/trunk@2880 e5f2f494-b856-4b98-b285-d166d9295462

src/bin/xfrin/TODO

@@ -63,3 +63,5 @@
     which a shutdown notification would be sent to the child.  With
     this approach each thread needs to watch at least two channels,
     and then it would need some asynchronous communication mechanism.
+17. Do zone transfer from notifyfrom address first, if it's one master of the zone.
+