r10486: This is a merge of Brad Henry's 'net join' rework, to better perform

r10486: This is a merge of Brad Henry's 'net join' rework, to better perform
an ADS join, particularly as a DC.  This represents the bulk of his
Google SOC work, and I'm very pleased to intergrate it into the tree.
(Metze will intergrate the DRSUAPI work later).

Both metze and myself have also put a lot of time into this patch, and
in mentoring Brad in general.  In return, Brad has been a very good
student, and has taken the comments well.

Since it's last appearance on samba-technical@, I have made
correctness and valgrind fixups, as well as adding a new 'BINDING'
mode to the libnet_rpc routines.  This allows the exact binding string
to be passed down from the torture code, including options and exact
target host.

Andrew Bartlett
(This used to be commit d6fa105fdabbeb83a9b0e50dad49d1649afdb2a4)