new DC join code

[tridge at samba.org]

Hi Metze,

 > Does the python join code, use the same network operations
 > as the C code (and as Windows servers)?

no

 > I think we should make sure a network capture of a samba dc join
 > and a windows dc join look exactly the same.

There is not one join process that windows uses - different versions
of windows use different join processes. 

What I aimed for is:

 - the final result in terms of the resulting objects is the same,
   except where the previous join was buggy (eg. the previous join
   didn't setup all of the serverreference elements). I used ldapcmp
   to compare the resulting join with the 'vampire' join.

 - an easy to understand and maintain join implementation

When we were first implementing domain join in Samba it was useful
that we closely match the windows join process for some version of
windows as it helped us with debugging. We're well beyond that stage
now, and DC join is routine. I think it is now far more important that
our join code we maintainable than that we follow the quirks of a
particular version of windows.

Cheers, Tridge