r12227: I realised that I wasn't yet seeing authenticated LDAP for the ldb

r12227: I realised that I wasn't yet seeing authenticated LDAP for the ldb
backend.

The idea is that every time we open an LDB, we can provide a
session_info and/or credentials.  This would allow any ldb to be remote
to LDAP.  We should also support provisioning to a authenticated ldap
server.

(They are separate so we can say authenticate as foo for remote, but
here we just want a token of SYSTEM).

Andrew Bartlett
(This used to be commit ae2f3a64ee0b07575624120db45299c65204210b)