Bug#689567: mkinitramfs: Module unix no longer automatically loaded causing udevadm to fail with socket error

[Avernar <avernar@gmail.com>]

Now that I think about it, the reason I made unix a module why back
was because initramfs gave errors that it wasn't a module during boot.
 I have since tracked down the change to the udev package as I was
unaware that the udev package was responsible for the force loading of
the unix module in the first place.

What worries me is that anybody upgrading an old Debian install with a
custom kernel and modular unix will end up with an unbootable system
after upgrading to wheezy.  I will raise this issue with the udev
maintainer.