devices are enumerated regardless of of the LIBUSB_HOTPLUG_ENUMERATE
flag. Make sure when the flag is not specified no arrival events are
generated for currently enumerated devices.
MFC after: 3 days
Sponsored by: Mellanox Technologies
libusb_hotplug_deregister_callback() for the LibUSB v1.0 API and
update the libusb(3) manual page.
Approved by: re (kib)
Requested by: swills
MFC after: 1 week