s3-net: use talloc array in share allowedusers

s3-net: use talloc array in share allowedusers

Bug: https://bugzilla.samba.org/show_bug.cgi?id=11426

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Ralph Böhme <slow@samba.org>
Autobuild-Date(master): Tue Aug  4 16:48:36 CEST 2015 on sn-devel-104

(cherry picked from commit 95eb6db580678a29b1f5f30a9567ea449a43d75a)

Autobuild-User(v4-1-test): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(v4-1-test): Mon Aug 17 20:01:19 CEST 2015 on sn-devel-104