udevd should probably clean up or at least ignore things from /dev/.udev/queue/
that are there from before it started to avoid long timeouts when we run udev in
the initrd and then kill it while preserving /dev (to allow the udevd from the
actual filesystem to run)

Encoding this sort of thing in the initrd's /init is almost certainly doomed to
failure down the line when udev changes implementation details of how it works.