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_snmp.c b/ospfd/ospf_snmp.c
index 78435de..604766d 100644
--- a/ospfd/ospf_snmp.c
+++ b/ospfd/ospf_snmp.c
@@ -1994,9 +1994,7 @@
     rn = route_top (ospf_snmp_vl_table);
   else
     {
-      rn = route_node_lookup (ospf_snmp_vl_table, (struct prefix *) &lp);
-      if (!rn)
-	return NULL;
+      rn = route_node_get (ospf_snmp_vl_table, (struct prefix *) &lp);
       rn = route_next (rn);
     }