Remove zonefile from nsd config

The zonefile isn't required in the config file as we are just
transfering from adns1.  Since we don't create the directory for the
files, it results in warnings in the nsd logs -- this can be a
confusing red-herring in a debugging situation.

Change-Id: I3e16a359549707a4a3967f580161dec9e71ab689
Related-Bug: https://www.nlnetlabs.nl/bugs-script/show_bug.cgi?id=4244

playbooks/roles/nameserver/templates/nsd.conf.j2

@@ -35,7 +35,6 @@ key:
 {% for zone in dns_zones %}
 zone:
     name: {{ zone.name }}
-    zonefile: /var/lib/nsd/zone/{{ zone.name }}
     allow-notify: {{ dns_master }} NOKEY
     request-xfr: AXFR {{ dns_master }} tsig
 {% endfor %}