Merge 'session_deleted_bug' into 'trunk'

Merge 'session_deleted_bug' into 'trunk'

r11775@t0mlaptop (orig r11740):  jsut | 2009-11-04 19:36:52 +0000
Branch to commit failing tests
r11777@t0mlaptop (orig r11742):  jsut | 2009-11-04 19:53:19 +0000
Added a failing test for a situation that occurs when you have a cookie for a session that's expired.  If you subsequently call 'session_is_valid' in the same request, the newly created session is deleted for being expired, despite the fact it was just created.

r11779@t0mlaptop (orig r11744):  jsut | 2009-11-04 21:38:49 +0000
This patch makes it so that the expiry is not looked up in the underlying store when a session has not yet committed to the store.
Probably not the most graceful way to do it, but it works.