packaging: Set default limit for core file size in service files

packaging: Set default limit for core file size in service files

This change adds the missing LimitCORE variable setting in nmb and
winbind service files to have no limit for coredumps by default.

Signed-off-by: Anoop C S <anoopcs@redhat.com>
Reviewed-by: Jose A. Rivera <jarrpa@samba.org>
Reviewed-by: Guenther Deschner <gd@samba.org>
Autobuild-User(master): Günther Deschner <gd@samba.org>
Autobuild-Date(master): Wed May 18 19:26:49 CEST 2016 on sn-devel-144