bgpd: more SAFI fixes

Two macros resolving to the same integer constant broke a case block and
a more thorough merge of BGP_SAFI_VPNV4 and BGP_SAFI_VPNV6 was
performed.

* bgpd.h: MPLS-labeled VPN SAFI is AFI-independent, switch to single
* macro
* bgp_capability_test.c: update test data
* bgp_mp_attr_test.c: idem
* bgp_route.c: (bgp_maximum_prefix_overflow, bgp_table_stats_vty) update
  macro and check conditions (where appropriate)
* bgp_packet.c: (bgp_route_refresh_send, bgp_capability_send,
  bgp_update_receive, bgp_route_refresh_receive): idem
* bgp_open.c: (bgp_capability_vty_out, bgp_afi_safi_valid_indices,
  bgp_open_capability_orf, bgp_open_capability): idem
* bgp_attr.c: (bgp_mp_reach_parse, bgp_packet_attribute,
  bgp_packet_withdraw): idem
diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 3f4b3ce..f34a756 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -1367,7 +1367,7 @@
       return -1;
     }
  
-  if (safi != BGP_SAFI_VPNV4)
+  if (safi != SAFI_MPLS_LABELED_VPN)
     {
       ret = bgp_nlri_sanity_check (peer, afi, stream_pnt (s), nlri_len);
       if (ret < 0) 
@@ -1411,7 +1411,7 @@
   
   withdraw_len = length - BGP_MP_UNREACH_MIN_SIZE;
 
-  if (safi != BGP_SAFI_VPNV4)
+  if (safi != SAFI_MPLS_LABELED_VPN)
     {
       ret = bgp_nlri_sanity_check (peer, afi, stream_pnt (s), withdraw_len);
       if (ret < 0)
@@ -2094,7 +2094,7 @@
       sizep = stream_get_endp (s);
       stream_putc (s, 0);	/* Length of this attribute. */
       stream_putw (s, AFI_IP);	/* AFI */
-      stream_putc (s, BGP_SAFI_VPNV4);	/* SAFI */
+      stream_putc (s, SAFI_MPLS_LABELED_VPN);	/* SAFI */
 
       stream_putc (s, 12);
       stream_putl (s, 0);
@@ -2257,7 +2257,7 @@
   if (safi == SAFI_MPLS_VPN)
     {
       /* SAFI */
-      stream_putc (s, BGP_SAFI_VPNV4);
+      stream_putc (s, SAFI_MPLS_LABELED_VPN);
 
       /* prefix. */
       stream_putc (s, p->prefixlen + 88);