Allow rtsol keyword in hostname.if(5) with net.inet6.ip6.forwarding=1.

"inet6 autoconf" was working before and rtsol should behave the same.
OK phessler

src/etc/netstart

@@ -1,6 +1,6 @@
 #!/bin/sh -
 #
-#	$OpenBSD: netstart,v 1.144 2014/12/03 19:55:49 florian Exp $
+#	$OpenBSD: netstart,v 1.145 2015/06/06 13:13:07 florian Exp $
 
 # Strip comments (and leading/trailing whitespace if IFS is set)
 # from a file and spew to stdout
@@ -242,13 +242,8 @@ ifmstart "" "trunk svlan vlan carp gif gre pfsync pppoe tun bridge"
 ifmstart "trunk svlan vlan carp"
 
 if [ "$ip6kernel" = "YES" -a "x$rtsolif" != "x" ]; then
-	fw=`sysctl -n net.inet6.ip6.forwarding`
-	if [ "x$fw" = "x0" ]; then
-		echo "IPv6 autoconf:$rtsolif"
-		ifconfig $rtsolif inet6 autoconf
-	else
-		echo "IPv6 autoconf not supported while IPv6 forwarding is enabled"
-	fi
+	echo "IPv6 autoconf:$rtsolif"
+	ifconfig $rtsolif inet6 autoconf
 fi
 
 # Look for default routes in /etc/mygate.