bug#2585: 23.0.90; read-file-name with dialog

[MJ]

When read-file-name is called and uses windows dialog to read a file
name, the 'dir' parameter has to be ended with '/'. It it does not,
the last part of the path name is used as the filename while the
default directory is the stripped 'dir' without last part. This does
not happen in Emacs 22. 

In minibuffer, there is comment that says: 

        ;; If DIR contains a file name, split it.

I'm not sure if that is the right thing to do. At least, it breaks the
compatibility with previous Emacs version. 

Is this an intended change?

Thanks. 

--
In GNU Emacs 23.0.90.1 (i386-mingw-nt5.1.2600)
 of 2009-02-22 on T42
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4) --cflags -I../../GnuWin32/include'