* RDEPENDing on libudev always selects udev as provider (even when systemd
should be used), for details see:
https://bugzilla.yoctoproject.org/show_bug.cgi?id=3622
* don't import pyudev from setup.py to get right pyudev version, this does
not work without pyudev installed
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>