ox-html: Fix Usenet links

* lisp/ox-html.el (org-html-link): Properly export Usenet links.

Reported-by: Michael Welle <mwe012008@gmx.net>
<http://permalink.gmane.org/gmane.emacs.orgmode/105915>

lisp/ox-html.el

@@ -2827,7 +2827,7 @@ INFO is a plist holding contextual information.  See
 	 (desc (org-string-nw-p desc))
 	 (path
 	  (cond
-	   ((member type '("http" "https" "ftp" "mailto"))
+	   ((member type '("http" "https" "ftp" "mailto" "news"))
 	    (org-link-escape-browser
 	     (org-link-unescape (concat type ":" raw-path))))
 	   ((string= type "file")