Revert "ospfd: Use route_node_lookup() instaed of route_node_get()"

This reverts commit c9b07581e0df8867499e97e08b382b6d3cc9c4c4.

See: http://patchwork.quagga.net/patch/410/
diff --git a/ospfd/ospf_abr.c b/ospfd/ospf_abr.c
index 5c30809..e172e53 100644
--- a/ospfd/ospf_abr.c
+++ b/ospfd/ospf_abr.c
@@ -133,9 +133,7 @@
     rn = route_top (area->ranges);
   else
     {
-      rn = route_node_lookup (area->ranges, (struct prefix *) &p);
-      if (!rn)
-	return NULL;
+      rn = route_node_get (area->ranges, (struct prefix *) &p);
       rn = route_next (rn);
     }