bug#12443: 24.2.50; Default values in the minibuffer prompt (fix inconsisntecy)

[Juri Linkov]

There is another consequence from the commit de4f347901a.

Is there a real need to duplicate the default value in read-file-name
when the default value is already shown as initial input?

For example, now after typing 'C-x 5 d' (dired-other-frame), the prompt
becomes overly long with the duplicate long default value that now
doesn't fit into the frame width:

  Dired in other frame (directory) 
[/very/long/path/with/lots/of/subdirectories/]: 
/very/long/path/with/lots/of/subdirectories/

Here the default value is in square brackets [...] because of my
customized prompt " [%s]" for minibuffer-default-prompt-format.
But with the default format " (default %s)" the prompt would be even longer.