[Samba] User ID gotcha with winbindd when adding local Unix accounts

[David Brodbeck]

Just noticed a somewhat subtle gotcha when adding users to a Red Hat Linux
system running winbindd.

If you use 'adduser', it will see your winbindd uid range and think all the
UIDs up to that point are in use. It'll then pick the next available one and
use that for the new user ID.  Winbindd, unaware of this, will go ahead and
pick that UID for the next user you add to the NT domain!

This didn't come to my attention until I added a new domain user and found
he had the same UID as a local administrative Unix account.