Short command receive timeout in nntpservice would cause partial commands to be received/split and discarded

Regarding commit 04340d91

I noticed after this, I would sometimes go to a message and my nntp client would say that the message could be loaded. I'm using claws-mail.

Just now, Accession asked me I was having this issue and he is using Thunderbird so it looks like the nntpserver may be having issues reopening the message base and reading the requested file.

Please revisit. Thanks.