[Seaside] 2.1 preview - cookie crumbles

[tblanchard@mac.com]

I created a new application and for the heck of it set useCookies to 
true.

This resulted in a broken session with a nil sessionKey.  I went back 
to configure and unset the useCookies checkbox but I still couldn't get 
a page up because I kept getting the old session walkback.  I think 
maybe setting this flag or unsetting this flag ought to toss the 
session cache out.

Anyhow I finally got an inspector on it and set sessionKey to some 
string and life was OK.