fixes an assert which doesnt seem to take into account that route_node_get
may return an existing node. (if the code wants a /new/ node why not use
route_node_set? if it doesnt mind - then the assert is wrong).

this bug is in zebra.org CVS. (must be an extremely rare/unlikely bug
though).
diff --git a/ospfd/ospf_interface.c b/ospfd/ospf_interface.c
index f030027..d94cdb8 100644
--- a/ospfd/ospf_interface.c
+++ b/ospfd/ospf_interface.c
@@ -135,7 +135,10 @@
   p.prefixlen = IPV4_MAX_PREFIXLEN;
 
   rn = route_node_get (IF_OIFS (ifp), &p);
-  assert (! rn->info);
+  /* rn->info should either be NULL or equal to this oi
+   * as route_node_get may return an existing node
+   */
+  assert (! rn->info || rn->info == oi);
   rn->info = oi;
 }