bgpd: IPv6 MP-BGP Routes addition and deletion

This patch contains the following:
1. Addition of IPv6 SAFI_MULTICAST BGP routes into the BGP Multicast RIB.
2. Deletion of IPv6 SAFI_MULTICAST BGP routes from the BGP Multicast RIB.
diff --git a/lib/zclient.h b/lib/zclient.h
index 8b3e71a..73389ec 100644
--- a/lib/zclient.h
+++ b/lib/zclient.h
@@ -167,6 +167,8 @@
 
   u_char message;
 
+  safi_t safi;
+
   u_char nexthop_num;
   struct in6_addr **nexthop;