Can't ask Gnus to check for all unknown groups

[Hallvard B Furuseth <h.b.furuseth@usit.uio.no>]

If you edit .newsrc.eld (and .newsrc if you have got one) and remove a
group, `gnus-group-find-new-groups' won't reinsert it if you have
	gnus-check-new-newsgroups = 'ask-server
	gnus-read-active-file     = 'some
That can happen if you tidy up .newsrc.eld "by hand" without considering
your gnus setup too closely.

So I suggest that `gnus-group-find-new-groups' gets a prefix arg which
causes it to in effect do
	(let ((gnus-check-new-newsgroups t)
              (gnus-read-active-file     t))
	  ...)
if gnus-save-killed-list is non-nil.

(If it did this for gnus-save-killed-list = nil, all the killed groups
would be reinserted in .newsrc.eld, which seems like a good way to start
a "chop up Lars with an axe"-competition.  Though of course
gnus-save-killed-list = nil could instead cause the new groups to be
listed in a *Killed Groups* buffer or something, from which the user
could pick his groups.  Or maybe something like that exists already?)

-- 
Hallvard