CVE-2021-20251: s4:auth: fix use after free in authsam_logon_success_accounting()

CVE-2021-20251: s4:auth: fix use after free in authsam_logon_success_accounting()

This fixes a use after free problem introduced by
commit 7b8e32efc336fb728e0c7e3dd6fbe2ed54122124,
which has msg = current; which means the lifetime
of the 'msg' memory is no longer in the scope of th
caller.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14611
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15253

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
(cherry picked from commit 1414269dccfd7cb831889cc92df35920b034457c)

Autobuild-User(v4-16-test): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(v4-16-test): Mon Dec 12 15:52:22 UTC 2022 on sn-devel-184