The install fast path treated an openable VHCI interface as 'driver
present', but the interface GUID is identical across all usbip-win2
releases while PLUGIN_HARDWARE_ONCE and STOP_ATTACH_ATTEMPTS only exist
since 0.9.7.5 — a machine with an older community release passed the
check and then failed every Plugin forever. The fast path now probes
STOP_ATTACH_ATTEMPTS and falls through to the (in-place, FORCE) install
when the driver lacks it. The probe's empty location doubles as
cleanup, discarding ghost reattach attempts left by a previous process.
4e9eedc1e8