agenda: Fix filter for day/week agenda

* lisp/org-agenda.el (org-agenda-filter-apply): Use the org-hd-marker
  to identify headlines instead of org-marker.

lisp/org-agenda.el

@@ -7731,7 +7731,7 @@ tags in the FILTER if any of the tags in FILTER are grouptags."
     (save-excursion
       (goto-char (point-min))
       (while (not (eobp))
-	(if (org-get-at-bol 'org-marker)
+	(if (org-get-at-bol 'org-hd-marker)
 	    (progn
 	      (setq tags (org-get-at-bol 'tags)
 		    cat (org-agenda-get-category)