Move `org-set-font-lock-defaults' from `org-set-regexps-and-options' to `org-mode'

* org.el (org-set-regexps-and-options): Don't set font-lock
defaults here.
(org-mode): Set font-lock defaults here.

This fixes the bug reported here:
http://article.gmane.org/gmane.emacs.orgmode/73429

lisp/org.el

@@ -5144,8 +5144,7 @@ Support for group tags is controlled by the option
 	    (mapcar (lambda (w) (substring w 0 -1))
 		    (list org-scheduled-string org-deadline-string
 			  org-clock-string org-closed-string)))
-      (org-compute-latex-and-related-regexp)
-      (org-set-font-lock-defaults))))
+      (org-compute-latex-and-related-regexp))))
 
 (defun org-file-contents (file &optional noerror)
   "Return the contents of FILE, as a string."
@@ -5331,6 +5330,7 @@ The following commands are available:
     (setq buffer-display-table org-display-table))
   (org-set-regexps-and-options-for-tags)
   (org-set-regexps-and-options)
+  (org-set-font-lock-defaults)
   (when (and org-tag-faces (not org-tags-special-faces-re))
     ;; tag faces set outside customize.... force initialization.
     (org-set-tag-faces 'org-tag-faces org-tag-faces))