mdssvc: fix returning file modification date for older Mac releases

mdssvc: fix returning file modification date for older Mac releases

Mac 10.10 uses kMDItemContentModificationDate instead of
kMDItemFSContentChangeDate.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15427

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Wed Jul 26 23:42:44 UTC 2023 on atb-devel-224

(cherry picked from commit c2e83ebe726b7bc42b329198214c784936f19888)

Autobuild-User(v4-18-test): Jule Anger <janger@samba.org>
Autobuild-Date(v4-18-test): Mon Jul 31 09:11:21 UTC 2023 on atb-devel-224