OpenZFS 8966 - Source file zfs_acl.c, function zfs_aclset_common contains a use after end of the lifetime of a local variable

Authored by: WHR <msl0000023508@gmail.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: Andriy Gapon <avg@FreeBSD.org>
Reviewed by: George Melikov <mail@gmelikov.ru>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Approved by: Richard Lowe <richlowe@richlowe.net>
Ported-by: Giuseppe Di Natale <dinatale2@llnl.gov>

OpenZFS-issue: https://www.illumos.org/issues/8966
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c95549fcdc
Closes #7141