flush all old routes before adding new interfaces or routes.

ref: netbsd pr3228/misc, Matthias Scheler

src/etc/netstart

@@ -1,6 +1,6 @@
 #!/bin/sh -
 #
-#	$OpenBSD: netstart,v 1.15 1997/03/03 01:13:11 downsj Exp $
+#	$OpenBSD: netstart,v 1.16 1997/04/07 22:18:05 rees Exp $
 
 # set these to "NO" to turn them off.  otherwise, they're used as flags
 routed_flags=-q
@@ -41,6 +41,8 @@ if [ -f /etc/defaultdomain ]; then
 	domainname `cat /etc/defaultdomain`
 fi
 
+route flush
+
 # Configure the IP filter before configuring network interfaces
 #
 if [ X"${ipfilter}" = X"YES" -a -f "${ipfilter_rules}" ]; then