[zebra] linux policy routing support with ipv6

Quagga support linux policy routing (ip route ... table $X) with zebra.conf
table $X option.  It works fine on ipv4.  On ipv6 the parameter is ignored
(table 0 is used).

* zebra/...: Pass appropriate table arg to rib_{add,delete}_ipv6
diff --git a/zebra/connected.c b/zebra/connected.c
index c776408..95399fa 100644
--- a/zebra/connected.c
+++ b/zebra/connected.c
@@ -342,7 +342,7 @@
     return;
 #endif
 
-  rib_add_ipv6 (ZEBRA_ROUTE_CONNECT, 0, &p, NULL, ifp->ifindex, 0,
+  rib_add_ipv6 (ZEBRA_ROUTE_CONNECT, 0, &p, NULL, ifp->ifindex, RT_TABLE_MAIN,
                 ifp->metric, 0);
 
   rib_update ();