Ignore IPP-over-USB devices if ipp-usb claims them #211
Description
This is basically a clone of CUPS issue, which is applicable to printer application written by PAPPL as well.
The core idea:
- find the device on USB
- check whether the same device is not advertised on mDNS already - which means ipp-usb is running and advertises it
- if the device is advertised, ignore it in PAPPL's USB backend