zebra: return route_node from rib_match_ipv4_safi

The multicast code needs to know the route_node in addition to the rib
entry in order to perform distance or prefix-length comparisons.  Add it
as optional "out" pointer parameter.

Cc: Everton Marques <everton.marques@gmail.com>
Cc: Balaji G <balajig81@gmail.com>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/zebra/rib.h b/zebra/rib.h
index 5eedfde..347fadb 100644
--- a/zebra/rib.h
+++ b/zebra/rib.h
@@ -418,7 +418,8 @@
 		            struct in_addr *gate, unsigned int ifindex, 
 		            u_int32_t, safi_t safi);
 
-extern struct rib *rib_match_ipv4_safi (struct in_addr addr, safi_t safi, int skip_bgp);
+extern struct rib *rib_match_ipv4_safi (struct in_addr addr, safi_t safi,
+					int skip_bgp, struct route_node **rn_out);
 
 extern struct rib *rib_lookup_ipv4 (struct prefix_ipv4 *);