bug#17554: 24.3.91; [Regression] re-usage of dired *Marked Files* buffer window

[Juri Linkov]

>> +(add-to-list 'display-buffer-alist '("\\*Completions\\*" 
>> display-buffer-at-bottom (nil)))
>
> `display-buffer-alist' has to stay nil by default.

This will do the same without changing the default value of 
`display-buffer-alist':

=== modified file 'lisp/minibuffer.el'
--- lisp/minibuffer.el  2014-06-02 00:18:22 +0000
+++ lisp/minibuffer.el  2014-06-06 22:55:17 +0000
@@ -1796,7 +1796,10 @@ (defun minibuffer-completion-help (&opti
              ;; window, mark it as softly-dedicated, so bury-buffer in
              ;; minibuffer-hide-completions will know whether to
              ;; delete the window or not.
-             (display-buffer-mark-dedicated 'soft))
+             (display-buffer-mark-dedicated 'soft)
+            (temp-buffer-show-function
+             (lambda (buffer)
+               (temp-buffer-window-show buffer '(display-buffer-at-bottom)))))
         (with-output-to-temp-buffer "*Completions*"
           ;; Remove the base-size tail because `sort' requires a properly
           ;; nil-terminated list.