bug#12128: 24.1.50; Default argument for `save-buffer'

[Dani Moncayo]

>> In any case, what I what to request here is that "M-n", insetead of the
>> error, brings to the minibuffer a default argument consisting in the
>> concatenation of the current directory and the name of the buffer.
>
> This patch implements this:

It does the job.  Thank you so much.

-- 
Dani Moncayo