r10810: This adds the hooks required to communicate the current user from the

r10810: This adds the hooks required to communicate the current user from the
authenticated session down into LDB.  This associates a session info
structure with the open LDB, allowing a future ldb_ntacl module to
allow/deny operations on that basis.

Along the way, I cleaned up a few things, and added new helper functions
to assist.  In particular the LSA pipe uses simpler queries for some of
the setup.

In ldap_server, I have removed the 'ldasrv:hacked' module, which hasn't
been worked on (other than making it continue to compile) since January,
and I think the features of this module are being put into ldb anyway.

I have also changed the partitions in ldap_server to be initialised
after the connection, with the private pointer used to associate the ldb
with the incoming session.

Andrew Bartlett