[K12OSN] How to turn off dadburn spatial browsing?

[Mike Ely <mely rogueriver k12 or us>]

[Edit: I think using special (curseword) chars in the subject line 
killed the first sending of this message.  If not, please forgive the 
double-post]

So I just got my k12LTSP server up and running, and have logged in with
a test account.  Unfortunately, it wants to use the astonishingly
_stupid_ gnome default spatial browsing (AKA "let's pretend we're on a
System 7 Mac or Win3.1 - isn't it modern?), which in the hands of a
bunch of seventh-graders is going to be an intractable mess very quickly.

So how do I set the system-wide default to whatever fugliness gnome
offers that's not "Open a new window with each directory opened?"

Cheers,
Mike