org: Fix security prompt for downloading remote resource

* lisp/org.el (org--confirm-resource-safe): Do not assume that
resource is safe when user replies "n" (do not download).

Reported-by: Max Nikulin <manikulin@gmail.com>
Link: https://orgmode.org/list/upj6uk$b7o$1@ciao.gmane.io

lisp/org.el

@@ -4685,7 +4685,7 @@ returns non-nil if any of them match."
                               (if (and (= char ?f) current-file)
                                   (concat "file://" current-file) uri))
                              "\\'")))))
-          (prog1 (memq char '(?y ?n ?! ?d ?\s ?f))
+          (prog1 (memq char '(?y ?! ?d ?\s ?f))
             (quit-window t)))))))
 
 (defun org-extract-log-state-settings (x)