[Nut-upsdev] USB Device match

[Edgar Fuß]

> I tried to add it back (see the #if 0 part in the attached patch) using libusb_get_port_number()) but at least on my NetBSD machine, it turned out to be zero for both devices.
> I resorted to using the loop variable instead (see the #else branch), which made my UPSen work again.
I pushed that change to my branch that introduced the Device property.

> Does libusb_get_port_number() return anything useful on other OSes?
No-one?