smbd:smb2: fix crash when smb2 session reauth fails

smbd:smb2: fix crash when smb2 session reauth fails

https://bugzilla.samba.org/show_bug.cgi?id=10208

Authentication error in smb2 session reauth invalidates
the session. In this case the session must in contrast
to successful session setup requests be torn down and live
no longer than the request.

The talloc move of the session from the global session
table to the request ensures that the session setup
reply can still be correctly signed, but subsequent
requests on the connection don't find a session any more.

Pair-Programmed-With: Jeremy Allison <jra@samba.org>
Pair-Programmed-With: Stefan Metzmacher <metze@samba.org>

Signed-off-by: Michael Adam <obnox@samba.org>