Bugfix: Keep todo keyword list valid

An entry `#+TODO:' without content make `M-x org-mode' fail.
While it may cause problems to have no TODO keywords defined, this
should not make entering the mode fail.

lisp/ChangeLog

@@ -1,5 +1,8 @@
 2009-08-12  Carsten Dominik  <carsten.dominik@gmail.com>
 
+	* org.el (org-set-regexps-and-options): Make sure the list of done
+	keywords is not invalid.
+
 	* org-exp.el (org-export-interpolate-newlines): New function.
 
 2009-08-11  Carsten Dominik  <carsten.dominik@gmail.com>

lisp/org.el

@@ -3697,7 +3697,8 @@ means to push this value onto the list in the variable.")
 
       ;; Compute the regular expressions and other local variables
       (if (not org-done-keywords)
-	  (setq org-done-keywords (list (org-last org-todo-keywords-1))))
+	  (setq org-done-keywords (and org-todo-keywords-1
+				       (list (org-last org-todo-keywords-1)))))
       (setq org-ds-keyword-length (+ 2 (max (length org-deadline-string)
 					    (length org-scheduled-string)
 					    (length org-clock-string)