bgpd: fix SAFI for for MPLS labeled VPN-IPv6

* bgpd.h: change value of BGP_SAFI_VPNV6 to 128 (RFC4659, BZ#659)
* bgp_route.c: (bgp_table_stats_vty) fix length argument to strncmp()
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index 75a59cb..1da5d1d 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -9090,7 +9090,7 @@
         safi = SAFI_UNICAST;
       else if (strncmp (safi_str, "vpnv4", 5) == 0)
         safi = BGP_SAFI_VPNV4;
-      else if (strncmp (safi_str, "vpnv6", 6) == 0)
+      else if (strncmp (safi_str, "vpnv6", 5) == 0)
         safi = BGP_SAFI_VPNV6;
       else
         {