Bug#803476: lvm2: lvchange hangs during initramfs local-top/lvm2 with latest udev

[Ian Campbell]

Forgot to say, the good versions of {libudev1,udev} are 215-17+deb8u2
and known bad are 227-2.

I'll do a little bit of bisection over 
http://snapshot.debian.org/package/systemd/ and see if I can narrow it
down a bit.

Ian.