/usr/lib/linux-tools/4.4.0-21-generic/usbipd is in linux-tools-4.4.0-21-generic 4.4.0-21.37.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/linux-tools/4.4.0-21-generic/../../linux-tools-4.4.0-21/usbipd