[Samba] recreating domain with existing gid and uid

[Axel Kittenberger]

On of the database files in /private was reported to corrupted by
samba_backup, so I played it safe and spend today to redo the domain from
scratch and rejoined every pc and recreated all user and group accounts.
And yes I did ran that hidden samba_backup thing this time right afterward.
This one is a small domain anyway, thats why I felt it as good testcase to
go for samba4 for a chance too.

One part of the question was tough, if it matters if one changes the cpu
architecture when importing a backup. or if other libs matter. Not that it
matters for my case anymore.