compatibility fixes for fda70440f4

* testing/lisp/test-ob-lob.el (test-ob-lob/call-with-header-arguments):
  Replace `cl-letf' with `letf' for compatibility with older Emacsen.
* testing/lisp/test-org-timer.el (test-org-timer/other-timer-error):
  Also check for 'error since 'user-error is not used by older Emacsen.

testing/lisp/test-ob-lob.el

@@ -39,7 +39,7 @@
 
 (ert-deftest test-ob-lob/call-with-header-arguments ()
   "Test the evaluation of a library of babel #+call: line."
-  (cl-letf (((symbol-function 'org-babel-insert-result)
+  (letf (((symbol-function 'org-babel-insert-result)
 	     (symbol-function 'ignore)))
     (org-test-at-id "fab7e291-fde6-45fc-bf6e-a485b8bca2f0"
       (move-beginning-of-line 1)

testing/lisp/test-org-timer.el

@@ -263,13 +263,13 @@ Also, mute output from `message'."
    (test-org-timer/with-temp-text ""
      (org-timer-start)
      (org-timer-set-timer 10))
-   :type 'user-error)
+   :type (list 'error 'user-error))
   ;; Countdown timer is running.
   (should-error
    (test-org-timer/with-temp-text ""
      (org-timer-set-timer 10)
      (org-timer-start))
-   :type 'user-error))
+   :type (list 'error 'user-error)))
 
 (provide 'test-org-timer)
 ;;; test-org-timer.el end here