Fix frame-restore wrt. version 20130920.1821 of f

The syntax of f-write is different from the one used; without this fix, frame-restore prevents me from closing Emacs.

Now, this is of course not a *proper* fix, as I'm no Lisp programmer, and I don't have any idea of how to depend on specific versions of a package ('f' in this case). But it does allow to close me Emacs.

Note also that the fixed frame-restore seems to save correctly `~/.emacs.d/frame-restore-parameters`, but not to restore the parameters in there.

I'm uninstalling frame-restore anyway, as I'm switching to a more comprehensive package which restores all frames, their splits, and so on.