This change added the latest upstream changes since version 1.0.0.

When using the smart plugin from collectd, there are problems with the
function udev_enumerate_scan_devices. This function is blocked and no
longer returns. Backporting the latest fixes from libudev-zero solves
the problem.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

This is a more actively developed libudev shim.

Signed-off-by: Rosen Penev <rosenp@gmail.com>