Don't crash when attempting to read path->oi->ifp if oi doesn't exist any
more. I'm not sure if this read should be attempted at all, but I'm trying
to keep code safe AND stable.
diff --git a/ospfd/ospf_zebra.c b/ospfd/ospf_zebra.c
index ea90c84..06916ae 100644
--- a/ospfd/ospf_zebra.c
+++ b/ospfd/ospf_zebra.c
@@ -429,7 +429,7 @@
               nexthop = &path->nexthop;
               api.nexthop = &nexthop;
             }
-          else if (path->oi->ifp)
+          else if (ospf_if_exists(path->oi) && (path->oi->ifp))
             {
               SET_FLAG (api.message, ZAPI_MESSAGE_NEXTHOP);
               api.ifindex_num = 1;