(ITS#5330) back-null upgrade

[h.b.furuseth@usit.uio.no]

Full_Name: Hallvard B Furuseth
Version: HEAD
OS: 
URL: 
Submission from: (NULL) (129.240.6.233)
Submitted by: hallvard


I'll be upgrading back-null a bit.  At the moment just support for
Back-config, Modify-Increment Extension and empty rootpw.


Maybe grow it to a useful template of a nontrivial backend later
(after I learn how to write that), with access control, referrals,
various extensions...  Might be almost-unused and thus subject to
code rot, but less so than documentation of the backend API.

However I imagine that could slow it down somewhat, so it might
become less useful when used to benchmark backends.  (E.g. if you
run a test with some backend, then with back-null, diff the time
to see how much was spent in the backend.)