interfaces: manual cache invalidate for previous

Purge the file on all known dynamic spots that run a deconfigure
of some sort.  We probably need something for a forced reload as
well but for now let's see if this works in general.

src/etc/inc/interfaces.inc

@@ -2766,6 +2766,7 @@ EXIT|RELEASE)
     /usr/local/sbin/ifctl -i ${wanif} -6nd
     /usr/local/sbin/ifctl -i ${wanif} -6sd
     /usr/local/sbin/ifctl -i ${wanif} -6pd
+    rm -f /tmp/${wanif}_cacheipv6 # XXX experiment
     /usr/local/sbin/configctl -d dns reload
     ;;
 *)

src/opnsense/scripts/interfaces/ppp-linkdown.sh

@@ -40,6 +40,8 @@ elif [ "${AF}" = "inet6" ]; then
 
 	/usr/local/sbin/ifctl -i ${IF} -6nd
 	/usr/local/sbin/ifctl -i ${IF} -6rd
+
+	rm -f /tmp/${IF}_cacheipv6 # XXX experiment
 fi
 
 /usr/local/sbin/configctl -d dns reload

src/opnsense/scripts/interfaces/rtsold_resolvconf.sh

@@ -70,6 +70,8 @@ elif [ "${1}" = "-d" ]; then
 	/usr/local/sbin/ifctl -i ${ifname} -6nd
 	/usr/local/sbin/ifctl -i ${ifname} -6sd
 
+	rm -f /tmp/${ifname%%:slaac}_cacheipv6 # XXX experiment
+
 	# reload DNS since data has been scrubbed
 	/usr/local/sbin/configctl -d dns reload
 fi