(org-agenda-align-tags): Replace use of cl `adjoin'.

lisp/org/org-agenda.el

@@ -4984,12 +4984,12 @@ the new TODO state."
 				(if line (point-at-eol) nil) t)
 	(add-text-properties
 	 (match-beginning 2) (match-end 2)
-	 (list 'face (delq nil (adjoin 'org-tag
-                                       (let ((prop (get-text-property
-                                                    (match-beginning 2) 'face)))
-                                         (if (listp prop)
-                                             prop
-                                           (list prop)))))))
+	 (list 'face (delq nil (let ((prop (get-text-property
+					    (match-beginning 2) 'face)))
+				 (or (listp prop) (setq prop (list prop)))
+				 (if (memq 'org-tag prop)
+				     prop
+				   (cons 'org-tag prop))))))
 	(setq l (- (match-end 2) (match-beginning 2))
 	      c (if (< org-agenda-tags-column 0)
 		    (- (abs org-agenda-tags-column) l)