[4.0.x] Status-Server with FreeRADIUS-Stats4 shows no output

[Milan Nikolic]

I understand status works differently now, but I can not find example,
test or any information about how can one now query Status-Server.

I send packet with TLV attribute and `FreeRADIUS-Stats4-Type` is set
to `Global` but I get nothing in debug output:

```
Sun Dec  2 01:09:32 2018 : Debug : (1)  proto_radius decode packet
  Code: Status-Server
  Id: 50
  Length: 52
  Vector: 7cab2806a1a0e3a98ed3c550382ee5ef
1a  0e  00002c50 (11344)  0f 08 01 06 00 00 00 01
50  12  1f 47 67 ef 79 c8 e0 e6 8c 49 aa d5 06 bc 57 b6
Sun Dec  2 01:09:32 2018 : Debug : Resetting worker 30 cleanup timer to +0s
Sun Dec  2 01:09:32 2018 : Debug : (1)  running request
Sun Dec  2 01:09:32 2018 : Debug : (1)  Received Status-Server ID 50
Sun Dec  2 01:09:32 2018 : Debug : (1)    FreeRADIUS-Stats4-Type = Global
Sun Dec  2 01:09:32 2018 : Debug : (1)    Message-Authenticator =
0x1f4767ef79c8e0e68c49aad506bc57b6
Sun Dec  2 01:09:32 2018 : Debug : (1)  Running 'recv Status-Server'
from file /etc/raddb/sites-enabled/status
Sun Dec  2 01:09:32 2018 : Debug : (1)  recv Status-Server {
Sun Dec  2 01:09:32 2018 : Debug : (1)    ok (ok)
Sun Dec  2 01:09:32 2018 : Debug : (1)  } # recv Status-Server (ok)
Sun Dec  2 01:09:32 2018 : Debug : (1)  Sent code 2 Id 50 from
192.168.0.31:18121 to 192.168.0.10:42101 via ens33 length 0
Sun Dec  2 01:09:32 2018 : Debug : (1)  done request
Sun Dec  2 01:09:32 2018 : Debug : (1)  proto_radius encode packet
  Code: Access-Accept
  Id: 50
  Length: 20
  Vector: 0a2f9c14653b3dccaf9503e94c0d3b7f
Sun Dec  2 01:09:32 2018 : Debug : (1)  finished request.
Sun Dec  2 01:09:32 2018 : Debug : freeing request
```

I tried many combinations, and also added `stats` to many send and
recv sections, is that needed now?
Can someone please give me some pointers, I tried looking at source at
some places but it is too complicated for me to follow.


Thanks