bug#24962: 26.0.50; list-buffers doesn't show buffers w/ name " "... visiting a file

[Eli Zaretskii]

> From: Tino Calancha <tino.calancha@gmail.com>
> Date: Fri, 18 Nov 2016 20:15:52 +0900 (JST)
> Cc: Tino Calancha <tino.calancha@gmail.com>
> 
> emacs -Q -eval '(write-region "foo" nil (expand-file-name 
> temporary-file-directory "foo"))'
>   M-: (find-file (expand-file-name temporary-file-directory "foo")) RET
>   M-: (rename-buffer " foo") RET
>   C-x C-b
>   ;; Buffer " foo" not listed.
> 
> >From the Emacs manual:
> doc/lispref/buffers.texi (Buffer Names):
> Buffers that are ephemeral and generally uninteresting to the user
> have names starting with a space, so that the @code{list-buffers} and
> @code{buffer-menu} commands don't mention them (but if such a buffer
> visits a file, it @strong{is} mentioned).

Thank.  Please add a test for this to the test suite.