hacking the .eld file b/c virtual groups are "read-only servers"

[Fritz Wuehler <fritz@spamexpire-201210.rodent.frell.theremailer.net>]

I've tried to make changes to the virtual groups in the *Server*
buffer, and I'm blocked because virtual groups are seen as "read-only"
servers.  I cannot kill a group (how do you remove one?), and cannot
edit a virtual group either.

So I have resorted to editing the *.newsrc.eld file.

I've been burnt with this approach.  After simplifying some of the
"nnvirtual" regular expressions so that many groups with a common
string are matched, e.g.

  {nnvirtual:^$\|\(^alt\.usenet$\)\|\(^alt\.culture\.usenet$\)}

becomes:

  {nnvirtual:^$\|usenet}

I get strange results, like gnus never finding new messages.