*: Widen width of Zserv routing tag field.

* lib/zebra.h: Introduce a route_tag_t type for route tags generally,
  and make it 4 bytes wide - so it can directly hold things like an ASN, or
  the OSPF ASE-LSA tag.
* zebra/rib.h: Use route_tag_t instead of u_short.
* *: Update 'u_short (*)?(tag|tmp)' to use route_tag_t instead of u_short.
  Update stream_{get,put} to l instead of w.
* ospf_zebra.c: (ospf_zebra_add) test OSPF tag within range of ROUTE_TAG_MAX.
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index bab9961..78cd53b 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -5605,7 +5605,7 @@
 void
 bgp_redistribute_add (struct prefix *p, const struct in_addr *nexthop,
 		      const struct in6_addr *nexthop6,
-		      u_int32_t metric, u_char type, u_short tag)
+		      u_int32_t metric, u_char type, route_tag_t tag)
 {
   struct bgp *bgp;
   struct listnode *node, *nnode;