In the replay case, the

	renew_client(session->se_client);

happens after we've droppped the sessionid_lock, and without holding a
reference on the session; so there's nothing preventing the session
being freed before we get here.

Thanks to Benny Halevy for catching a bug in an earlier version of this
patch.
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Acked-by: NBenny Halevy <bhalevy@panasas.com>