open https://gitlab.synchro.net/main/sbbs/-/issues/790

Commit 04340d911b1e7282cdb7411962eeb2de34c5309e may have broken nttp. It seems like the message base isn't reopened when a command it sent from the client to the nntpserver.

After a while I started getting

```
This message can't be displayed.
This is probably due to a network error.
```

The application reports this in the console

```
(claws-mail:620218): Claws-Mail-WARNING **: 15:16:46.700: can't read article 21741

(claws-mail:620218): Claws-Mail-WARNING **: 15:16:46.700: can't get message file path
```

In my usenet client.

I can see it try to get the article in the sbbs log

```
Sep 16 15:16:46 bbs synchronet: srvc 0052 NNTP [DOVE-Net.Synchronet_Programming] cmd: ARTICLE 21741
```

If I disconnect and reconnect then I get the message.
--- SBBSecho 3.20-Linux
* Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)

close https://gitlab.synchro.net/main/sbbs/-/issues/790
--- SBBSecho 3.20-Linux
* Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)

https://gitlab.synchro.net/main/sbbs/-/issues/790#note_5691

Looks like commit 04340d91 is closing after 5 seconds of inactivity according to the logs, but I'm perfectly fine with that. Just that the duration doesn't match the git log entry.
--- SBBSecho 3.20-Linux
* Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)

https://gitlab.synchro.net/main/sbbs/-/issues/790#note_5692

There was a commit with the message "Close an open message base after just 10 seconds of client inactivity ", so working as intended.
--- SBBSecho 3.20-Linux
* Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)

https://gitlab.synchro.net/main/sbbs/-/issues/790#note_5696

Ah yes, I see it now. thank you.
--- SBBSecho 3.20-Linux
* Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)