Add productId to the Wireshark dissector and udev rule, adjust the
serial path detection logic to find the right key
(`\Device\LGVZANDNETDIAG1`). Now you do not need to pass `--serial COM4`
anymore.
Reportedly fails in VirtualBox with USB passthrough, but works fine on
Linux. Thanks @invisiblek for testing!
The udev rules and Wireshark dissector still have idProduct hardcoded
for the time being, but lglaf.py detection logic is converted to use
heuristics instead.
Thanks to @invisiblek for testing and providing lsusb output.
