Do not expand title in <title> markups

If we expand `title', we may have HTML markup between the <title>
markups, which is not valid.

Signed-off-by: Julien Danjou <julien@danjou.info>

lisp/org-html.el

@@ -913,7 +913,7 @@ lang=\"%s\" xml:lang=\"%s\">
 		      "")
 		  (or charset "iso-8859-1"))
 		 language language
-		 (org-html-expand title)
+		 title
 		 (or charset "iso-8859-1")
 		 date author description keywords
 		 style