[imp] Fix for broken SQL session handlers since IMP 3.2.2

[Chuck Hagenbuch]

Quoting Michael Schout <mschout at gkg.net>:

> Apparently the reason that getCleanSession() does not succeed in
> changing the session id is that it calls:
>
> @session_destroy();
>
> before calling session_regenerate_id()
>
> If I remove the call to @destroy_session() inside getCleanSession(),
> then the session_regenerate_id() call succeeds and the client gets
> assigned a new session_id when they submit the login form.

Okay, interesting. Try what I just committed to both HEAD and RELENG_2.

-chuck

--
"Regard my poor demoralized mule!" - Juan Valdez