[imp] Remove folders listbox

[Chuck Hagenbuch]

Quoting Martin.Masse at cssamares.qc.ca:

> I tried to remove the folders listbox appear when I'm in IMP. I want keep
> "folders icons" but not the listbox. I changed this parameter in prefs.php
> :
>
> $conf['user']['allow_folders'] = false;
>
> But it's does'nt work (both listbox and icon disappeared).

Right, because that's the intended behavior.

What is the use case for this change?

-chuck