bgpd: display label as part of the PMSI tunnel attribute

bgpd: display label as part of the PMSI tunnel attribute

root@TORS1:~# net show bgp l2vpn evpn route rd 27.0.0.15:4 type multicast
EVPN type-2 prefix: [2]:[ESI]:[EthTag]:[MAClen]:[MAC]
EVPN type-3 prefix: [3]:[EthTag]:[IPlen]:[OrigIP]
EVPN type-5 prefix: [5]:[ESI]:[EthTag]:[IPlen]:[IP]

BGP routing table entry for 27.0.0.15:4:[3]:[0]:[32]:[27.0.0.15]
Paths: (1 available, best #1)
  Advertised to non peer-group peers:
  MSP1(uplink-1) MSP2(uplink-2)
  Route [3]:[0]:[32]:[27.0.0.15] VNI 1003
  Local
    27.0.0.15 from 0.0.0.0 (27.0.0.15)
      Origin IGP, weight 32768, valid, sourced, local, bestpath-from-AS Local, best
      Extended Community: ET:8 RT:5550:1003
      AddPath ID: RX 0, TX 10
      Last update: Thu Feb  7 00:17:24 2019
      PMSI Tunnel Type: Ingress Replication, label: 1003 >>>>>>>>>>>>>

Displayed 1 prefixes (1 paths) with this RD (of requested type)
root@TORS1:~#

Ticket: CM-23790

Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>