[leafnode-list] inaccurate response to GROUP command

[Brian Sammon]

> > leafnode will _NEVER_ decrement the "high watermark" even if some of the
> > articles with higher numbers have expired.
> 
> Hmm... it is not clear from the text of the standards whether this is 
> permitted or not.

Okay, it's pretty clear from my reading of news.software.nntp archives that 
leafnode's behavior is in keeping with the consensus of the NNTP community.

Maybe I'll pester the nntpext group to clarify the wording of the upcoming 
draft...