Bug#726390: switch to upstream udev rules

[email.bug at arcor.de]

Package: mdadm

Wondering about why nothing happened when hot-plugging a 
raid member drive, I found the following answer in the changelog:

* disabled the incremental assembly upstream turned on in 3.1.3 for
    now, this will have to wait until after the squeeze release.

And saw the Maintainer changed. Many thanks to all for maintaining 
the package in the past and ongoing!

Maybe it is possible to shed some light about the current state 
and the intentions of enabling upsteam's incremental/hotplug code 
(udev rules) in Debian?