Enable DNSSEC validation in unbound by default

OK deraadt@ otto@

src/etc/unbound.conf

@@ -1,4 +1,4 @@
-# $OpenBSD: unbound.conf,v 1.17 2019/08/25 15:50:21 ajacoutot Exp $
+# $OpenBSD: unbound.conf,v 1.18 2019/11/07 12:49:45 job Exp $
 
 server:
 	interface: 127.0.0.1
@@ -19,9 +19,9 @@ server:
 	hide-identity: yes
 	hide-version: yes
 
-	# Uncomment to enable DNSSEC validation.
+	# Perform DNSSEC validation. Comment out the below option to disable.
 	#
-	#auto-trust-anchor-file: "/var/unbound/db/root.key"
+	auto-trust-anchor-file: "/var/unbound/db/root.key"
 	#val-log-level: 2
 
 	# Uncomment to synthesize NXDOMAINs from DNSSEC NSEC chains