r16349: Another fix to make winbind more robust in large domains:

r16349: Another fix to make winbind more robust in large domains:

We may only feed rpc_useraliases with chunks of 1024 entries.  This is
important as the token generation otherwise fails when a user is member
of more then 1024 groups.

Volker, please check.

Guenther
(This used to be commit d8fd94648f965eb043f957b154ce63b245a90328)