My workaround :
- purge udev (this will remove initramfs-tool as well)
- install udev 0.93-1 from testing
- reboot : you will still have the error (coming from the initrd image
generated by initramfs-tools ran with udev 0.97)
- re-install initramfs-tools : will regenerate your initrd with the
correct version of udev
It worked on my system, I guess several variant could be possible, I'm
not sure if it is necessary to purge udev conf file, or to reboot but
that's how I did to get my PC back this mo