Where libinput is installed, checking whether the fuzz is applied to the
device will always fail with an error - the udev rules will remove the
fuzz and copy its value to the LIBINPUT_FUZZ properties instead.

So let's fix this: where the fuzz shows up on the device print a warning
because libinput's udev rule isn't working. And where it's missing check
the udev properties and compare those to the settings instead.

Fixes #472



Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>