bgpd: Evpn json cli output missing

bgpd: Evpn json cli output missing

Issue1: The following json cli commands are broken (they dont display
anything):
1. show [ip] bgp l2vpn evpn json
2. show [ip] bgp l2vpn evpn all neighbors <IP> routes json
3. show [ip] bgp l2vpn evpn rd <RD> json
4. show [ip] bgp l2vpn evpn rd <RD> neighbors <IP> routes json

RCA1: The existing json_object was partially filled.
Some fields like "prefix", "prefixLen", etc were not
filled in the json_object.
RCA2: Code missing to display the constructed json_object.

Issue2: Column header not shown on bgp evpn commands.
Fix: turned on the flag to display header

Output after fix:
The above commands have been made to follow the existing output style of
"show bgp l2vpn evpn routes json"
leaf-1# sh bgp l2vpn evpn json
{
  "bgpTableVersion":1,
  "bgpLocalRouterId":"10.100.0.1",
  "defaultLocPrf":100,
  "localAS":65000,
  "10.100.0.1:3":{
    "rd":"10.100.0.1:3",
    "[3]:[0]:[32]:[10.100.0.1]":{
      "prefix":"[3]:[0]:[32]:[10.100.0.1]",
      "prefixLen":288,
      "paths":[
        {
          "valid":true,
          "bestpath":true,
          "pathFrom":"external",
          "routeType":3,
          "ethTag":0,
          "ipLen":32,
          "ip":"10.100.0.1",
          "weight":32768,
          "peerId":"(unspec)",
          "aspath":"",
          "path":"",
          "origin":"IGP",
          "nexthops":[
            {
              "ip":"10.100.0.1",
              "afi":"ipv4",
              "used":true
            }
          ]
        }
      ]
    }
  },
..........
..........
  "10.100.0.2:2":{
    "rd":"10.100.0.2:2",
    "[3]:[0]:[32]:[10.100.0.2]":{
      "prefix":"[3]:[0]:[32]:[10.100.0.2]",
      "prefixLen":288,
      "paths":[
        {
          "valid":true,
          "bestpath":true,
          "pathFrom":"external",
          "routeType":3,
          "ethTag":0,
          "ipLen":32,
          "ip":"10.100.0.2",
          "weight":0,
          "peerId":"205.0.113.2",
          "aspath":"65002",
          "path":"65002",
          "origin":"IGP",
          "nexthops":[
            {
              "ip":"10.100.0.2",
              "afi":"ipv4",
              "used":true
            }
          ]
        },
        {
          "valid":true,
          "pathFrom":"external",
          "routeType":3,
          "ethTag":0,
          "ipLen":32,
          "ip":"10.100.0.2",
          "weight":0,
          "peerId":"203.0.113.4",
          "aspath":"65001 65002",
          "path":"65001 65002",
          "origin":"IGP",
          "nexthops":[
            {
              "ip":"10.100.0.2",
              "afi":"ipv4",
              "used":true
            }
          ]
        }
      ]
    }
  },
....
....
  "numPrefix":10,
  "totalPrefix":10
}
leaf-1# sh bgp l2vpn evpn
BGP table version is 1, local router ID is 10.100.0.1
Status codes:s suppressed, d damped, h history, * valid, > best, i - int
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
Route Distinguisher: ip 10.100.0.1:3

*> [3]:[0]:[32]:[10.100.0.1]
                    10.100.0.1                         32768 i
Route Distinguisher: ip 10.100.0.1:4

*> [3]:[0]:[32]:[10.100.0.1]
                    10.100.0.1                         32768 i
Route Distinguisher: ip 10.100.0.1:5

*> [3]:[0]:[32]:[10.100.0.1]
                    10.100.0.1                         32768 i
Route Distinguisher: ip 10.100.0.1:6

*> [3]:[0]:[32]:[10.100.0.1]
                    10.100.0.1                         32768 i
Route Distinguisher: ip 10.100.0.2:2

*> [3]:[0]:[32]:[10.100.0.2]
                    10.100.0.2                             0 65002 i
*  [3]:[0]:[32]:[10.100.0.2]
                    10.100.0.2                             0 65001 65002
Route Distinguisher: ip 10.100.0.2:3

*> [3]:[0]:[32]:[10.100.0.2]
                    10.100.0.2                             0 65002 i
*  [3]:[0]:[32]:[10.100.0.2]
                    10.100.0.2                             0 65001 65002
Route Distinguisher: ip 10.100.0.2:4

*> [3]:[0]:[32]:[10.100.0.2]
                    10.100.0.2                             0 65002 i
*  [3]:[0]:[32]:[10.100.0.2]
                    10.100.0.2                             0 65001 65002

Displayed 10 out of 10 total prefixes

Signed-off-by: Lakshman Krishnamoorthy <lkrishnamoor@vmware.com>