Following gnus links: Don't mark unrelated articles read

* lisp/org-gnus.el: (org-gnus-follow-link): Fix argument to
  gnus-group-read-group so that following a link does not result in
  unread article being selected.

The NO-ARTICLE argument to gnus-group-read-group should be t.
Otherwise org-gnus-follow-link selects the most unread article in a
group before selecting the linked article. This results in unread
articles being unread (which can cause one to miss important mail).

lisp/org-gnus.el

@@ -272,7 +272,7 @@ If `org-store-link' was called with a prefix arg the meaning of
 			       ;; stop on integer overflows
 			       (> articles 0))
 		     (setq group-opened (gnus-group-read-group
-					 articles nil group)
+					 articles t group)
 			   articles (if (< articles 16)
 					(1+ articles)
 				      (* articles 2))))