org-babel-result-to-file: Fix when in indirect buffer

* lisp/ob-core.el (org-babel-result-to-file): Consider file name in
base buffer when calculating base directory.

Reported-by: 赵一宇 <zhyznd@163.com>
Link: https://list.orgmode.org/orgmode/3d69c850.69db.18953ae45da.Coremail.zhyznd@163.com/

lisp/ob-core.el

@@ -2741,7 +2741,7 @@ specified as an an \"attachment:\" style link."
   (when (stringp result)
     (let* ((result-file-name (expand-file-name result))
            (base-file-name (buffer-file-name (buffer-base-buffer)))
-           (base-directory (and buffer-file-name
+           (base-directory (and base-file-name
                                 (file-name-directory base-file-name)))
            (same-directory?
 	    (and base-file-name