Ignore missing ifconfig error, we do this manually on the Hurd

Index: openvpn-2.1.3/tun.c
===================================================================
--- openvpn-2.1.3.orig/tun.c
+++ openvpn-2.1.3/tun.c
@@ -926,7 +926,7 @@ do_ifconfig (struct tuntap *tt,
       }
 
 #else
-      msg (M_FATAL, "Sorry, but I don't know how to do 'ifconfig' commands on this operating system.  You should ifconfig your TUN/TAP device manually or use an --up script.");
+      msg (M_INFO, "Sorry, but I don't know how to do 'ifconfig' commands on this operating system.  You should ifconfig your TUN/TAP device manually or use an --up script.");
 #endif
       argv_reset (&argv);
     }
