bgpd: fix "used" json key on link-local nexthop

When a peer has no IPv6 global address to send as nexthop, it sends the
IPv6 link-local instead as global. "show bgp ipv6 json" displays the
same address in global and link-local scopes.

> "nexthops": [
>   {
>     "ip": "fe80::a495:38ff:fea6:6ea3",
>     "afi": "ipv6",
>     "scope": "global",
>     "used": true
>   },
>   {
>     "ip": "fe80::a495:38ff:fea6:6ea3",
>     "afi": "ipv6",
>     "scope": "link-local"
>   }
> ]

However, "used" key is set on the global nexthop but not in link-local.
It is correct but it makes difficult to test JSON to expect the usage of
a link-local. The contrary is also correct.

Set "used" key on the link-local nexhop instead to facilitate the tests.

Signed-off-by: Louis Scalbert <[email protected]>

bgpd/bgp_route.c

@@ -9629,10 +9629,7 @@ void route_vty_out(struct vty *vty, const struct prefix *p,
 				json_object_string_add(json_nexthop_ll, "scope",
 						       "link-local");
 
-				if ((IPV6_ADDR_CMP(&attr->mp_nexthop_global,
-						   &attr->mp_nexthop_local) !=
-				     0) &&
-				    !CHECK_FLAG(attr->nh_flags,
+				if (!CHECK_FLAG(attr->nh_flags,
 						BGP_ATTR_NH_MP_PREFER_GLOBAL))
 					json_object_boolean_true_add(
 						json_nexthop_ll, "used");