bug#1285: 23.0.60; minibuffer-complete and `C-x d'

[Chong Yidong]

> When I type `C-x d <something> TAB', where `<something>' is any sequence
> of characters, then if `<something>' can complete to more than one
> directory name, then the *Completions* buffer displays only those
> directory names, but no non-directory file names.  But if `<something>'
> can complete to a non-directory file name, then it does.

I think the new completion behavior for C-x d is well-intentioned, but
too complicated.  Hence the user confusion reported here.  Stefan: WDYT
about switching back to the old version of dired-read-dir-and-switches?