(gnus-auto-expirable-marks): Remove `spam'.

(gnus-auto-expirable-marks): Remove `spam'.
(gnus-summary-mode-line-format-alist): Add %h for number of
spams.
(gnus-newsgroup-spam-marked): New variable.
(gnus-summary-local-variables): Add gnus-newsgroup-spam-marked.
(gnus-article-read-p, gnus-article-mark)
(gnus-set-global-variables, gnus-set-global-variables)
(gnus-article-marked-p, gnus-summary-mark-article-as-read)
(gnus-summary-mark-article-as-unread)
(gnus-summary-mark-article-as-unread, gnus-summary-mark-article)
(gnus-mark-article-as-read, gnus-mark-article-as-unread)
(gnus-mark-article-as-unread, gnus-summary-catchup): Grok spam.