Fix: `org-agenda-skip-scheduled-if-deadline-is-shown': show TODOs without deadline

* lisp/org-agenda.el (org-agenda-get-scheduled): If
  `org-agenda-skip-scheduled-if-deadline-is-shown' is set to
  'repeated-after-deadline, still show tasks without any deadline

The problem was that the check for the deadline seems to return a
default time even if no deadline is set for the task.  This adds a
check if there is a deadline at all, if there is none, the task is
shown in the agenda, otherwise the old semantics apply.

TINYCHANGE

lisp/org-agenda.el

@@ -6245,6 +6245,7 @@ an hour specification like [h]h:mm."
 		    category-pos (get-text-property (point) 'org-category-position))
 	      (if (and (eq org-agenda-skip-scheduled-if-deadline-is-shown
 			   'repeated-after-deadline)
+		       (org-get-deadline-time (point))
 		       (<= 0 (- d2 (time-to-days (org-get-deadline-time (point))))))
 		  (throw :skip nil))
 	      (if (not (re-search-backward "^\\*+[ \t]+" nil t))