Replace two leftover ttlval with duration

Since the introduction of durations, all ttlval configuration types
are replaced with durations.  Duration is an ISO 8601 duration, a
TTL-style value, or a number.  These two references were missed and
are now also replaced.

bin/named/named.conf.docbook

@@ -1017,7 +1017,7 @@ zone <replaceable>string</replaceable> [ <replaceable>class</replaceable> ] {
 
     <literallayout class="normal">
 dnssec-policy <replaceable>string</replaceable> {
-	dnskey-ttl <replaceable>ttlval</replaceable>;
+	dnskey-ttl <replaceable>duration</replaceable>;
 	keys { ( csk | ksk | zsk ) key-directory lifetime <replaceable>duration</replaceable> algorithm <replaceable>integer</replaceable> [ <replaceable>integer</replaceable> ] ; ... };
 	parent-ds-ttl <replaceable>duration</replaceable>;
 	parent-propagation-delay <replaceable>duration</replaceable>;

doc/arm/dnssec-policy.grammar.xml

@@ -13,7 +13,7 @@
 
 <programlisting>
 <command>dnssec-policy</command> <replaceable>string</replaceable> {
-    <command>dnskey-ttl</command> <replaceable>ttlval</replaceable>;
+    <command>dnskey-ttl</command> <replaceable>duration</replaceable>;
     <command>keys</command> { ( csk | ksk | zsk ) key-directory <replaceable>duration</replaceable> <replaceable>integer</replaceable> [ <replaceable>integer</replaceable> ] ; ... };
     <command>parent-ds-ttl</command> <replaceable>duration</replaceable>;
     <command>parent-propagation-delay</command> <replaceable>duration</replaceable>;