bgpd: Enable support for BGP IPV6 multipath.

This commit adds these two commands:
maximum-paths <1-MULTIPATH_NUM>
maximum-paths ibgp <1-MULTIPATH_NUM>

under address-family ipv6 mode.  In addition adding the ability
to pass multiple paths down into zebra from bgp.

Signed-off-by: Ayan Banerjee <ayan@cumulusnetworks.com>
Signed-off-by: Dinesh G Dutt <ddutt@cumulusnetworks.com>
Reviewed-by: Scott Feldman <sfeldma@cumulusnetworks.com>
diff --git a/bgpd/bgp_main.c b/bgpd/bgp_main.c
index 562afc2..eb0fe17 100644
--- a/bgpd/bgp_main.c
+++ b/bgpd/bgp_main.c
@@ -323,6 +323,8 @@
     zclient_free (zlookup);
   if (bgp_nexthop_buf)
     stream_free (bgp_nexthop_buf);
+  if (bgp_ifindices_buf)
+    stream_free (bgp_ifindices_buf);
 
   /* reverse bgp_master_init */
   if (bm->master)