idmap creation/deletion tool?

[Steven Danneman]

> > Yeah, the problem with that approach is the race condition on a live
> > system.  I'm happy to write a tool, probably fill in the net idmap
> > stubs, I just didn't want to duplicate work.
> 
> No duplication that I'm aware of.  Charge ahead.  Thanks.
> 

Actually, it looks like this may have already been provisioned for in a
generic way via winbindd with WINBINDD_SET_MAPPING.  It allows you to
create/change mappings, and is plumbed through to libwbclient, but not
yet to wbinfo.

idmap_tdb_remove_mapping() is also implemented, but has no corresponding
winbindd dispatch function. 

Filing out these features on the wbinfo -> winbindd path seems like the
cleaner approach, though I'd also like it to handle many-to-one
sid-to-id mappings which is a little tricky.

-Steven