Disable db file. It is believed to be a saner default for the common

use case.
sthen@ noticed a problem with missing records on shutdown.
OK sthen@

src/etc/nsd.conf

@@ -1,7 +1,8 @@
-# $OpenBSD: nsd.conf,v 1.8 2014/07/11 21:40:31 deraadt Exp $
+# $OpenBSD: nsd.conf,v 1.9 2015/03/10 18:11:35 florian Exp $
 
 server:
 	hide-version: yes
+	database: "" # disable database
 
 ## bind to a specific address/port
 #	ip-address: 192.0.2.53