Simplifying the multiple password backend code in HEAD and 3.0.

[jra at dp.samba.org]

Spurred on by some complaints in IRC :-) I took a look at the passdb
backend code in HEAD and 3.0.

It looks nice, but it's horribly complex for what it needs to do
(IMHO). Is there any real reason to have multiple possible backends
simultaneously in a cascaded interface ?

I can see the benefits of a plug-in architecture to allow different
backends to be tested, but what we need is to do *one* good backend
implementation (my vote would be for an LDAP one) and then use that
to implement others - modfying the interfaces as needed to support
any idiosyncracies that come out of the different backends.

If someone wants to change from one backend to another a decent
export_all/import_all interface method is all we need (probably
using the enumerate methods). Changing backends is a major thing
to do (IMHO) as it means moving data between different databases,
and I'm worried that the existing code makes it look as though you
can just change a parameter and have it happen automatically.

Comments welcome..... but I do want to start cutting out some of
this code soon.

Jeremy.