bgpd: Make bgp_info_cmp robust to paths that do not have su_remote info

My original su_remote == NULL check is not correct. It seems that

* bgp_route.c: (bgp_info_cmp) Some bgp_info is compared with su_remote=NULL
  and it's supposed to be perfectly legal.  E.g.  configured subnet announces
  ("network a.b.c.d/n"). Ensure bgp_info_cmp is robust if such a path gets
  as far as the neighbour address comparison step.
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index f401271..40012ac 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -564,7 +564,12 @@
     return 1;
   if (CHECK_FLAG (new->flags, BGP_INFO_STALE))
     return 0;
-
+  /* locally configured routes to advertise do not have su_remote */
+  if (new->peer->su_remote == NULL)
+    return 0;
+  if (exist->peer->su_remote == NULL)
+    return 1;
+  
   ret = sockunion_cmp (new->peer->su_remote, exist->peer->su_remote);
 
   if (ret == 1)