bug#28945: 25.2; desktop auto save timer does not work

[Drew Adams]

> > desktop.el says it saves status when Emacs is killed.
> > For that feature, why does it matter how long you have been editing?
> >
> > Does desktop.el now do more than that?
> 
> It does.  From the doc string:
> 
>   Once a desktop file exists, Emacs will auto-save it according
>   to the option ‘desktop-auto-save-timeout’.

Why is the default value 30 instead of just nil (OFF)?
To be compatible with past behavior the default value
would be nil, no?