Document need for net.inet.carp.preempt to be enabled.

ok markus@ henning@

src/etc/ifstated.conf

@@ -1,9 +1,11 @@
-# $OpenBSD: ifstated.conf,v 1.1 2004/02/04 23:49:36 mcbride Exp $
+# $OpenBSD: ifstated.conf,v 1.2 2004/03/17 23:58:27 mcbride Exp $
 # This is a sample config for a pair of firewalls with two interfaces
 #
 # carp0 and carp1 have ip addresses on 192.168.3.0/24 and 192.168.6.0/24
 # respectively. 
 
+# net.inet.carp.preempt must be enabled (set to 1) for this to work correctly.
+
 # Uncomment one of the following lines to force primary/backup status.
 # init state primary
 # init-state backup