s3-winexe: Fix winexe core dump (use-after-free)

s3-winexe: Fix winexe core dump (use-after-free)

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14893

Guenther

Signed-off-by: Guenther Deschner <gd@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
Autobuild-User(master): Günther Deschner <gd@samba.org>
Autobuild-Date(master): Fri Nov  5 11:43:57 UTC 2021 on sn-devel-184

(cherry picked from commit e9495d2ed28a26899dc3dd77bdfe56e284980218)

Autobuild-User(v4-15-test): Jule Anger <janger@samba.org>
Autobuild-Date(v4-15-test): Wed Nov 10 17:05:18 UTC 2021 on sn-devel-184