[netdevice] Ensure consistent interpretation of "netX" device name

Ensure that the "${netX/...}" settings mechanism always uses the same
interpretation of the network device corresponding to "netX" as any
other mechanism that performs a name-based lookup of a network device.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
diff --git a/src/net/netdev_settings.c b/src/net/netdev_settings.c
index cc2e103..fb98663 100644
--- a/src/net/netdev_settings.c
+++ b/src/net/netdev_settings.c
@@ -370,8 +370,8 @@
 static struct settings * netdev_redirect ( struct settings *settings ) {
 	struct net_device *netdev;
 
-	/* Redirect to most recently opened network device */
-	netdev = last_opened_netdev();
+	/* Redirect to "netX" network device */
+	netdev = find_netdev ( settings->name );
 	if ( netdev ) {
 		return netdev_settings ( netdev );
 	} else {