bgpd: fix wrong vrf name for debug

bgpd: fix wrong vrf name for debug

For vrf name in debug, use `bgp->name_pretty` instead of `bgp->name`.

Before:
```
2023/01/15 05:04:19 BGP: [P4GAZ-JHRM3] evpn vrf VRF default nh init
2023/01/15 05:04:19 BGP: [ZZKY3-FX5JH] bgp_get: Registering BGP instance (null) to zebra <-
2023/01/15 05:04:19 BGP: [TNK7N-FJF7K] Registering VRF 0
```

After:
```
2023/01/15 21:38:16 BGP: [P4GAZ-JHRM3] evpn vrf VRF default nh init
2023/01/15 21:38:16 BGP: [ZZKY3-FX5JH] bgp_get: Registering BGP instance VRF default to zebra <-
2023/01/15 21:38:16 BGP: [TNK7N-FJF7K] Registering VRF 0
```

Signed-off-by: anlan_cs <vic.lan@pica8.com>