/usr/lib/linux-tools/3.19.0-20-lowlatency/cpupower is in linux-tools-3.19.0-20-lowlatency 3.19.0-20.20~14.04.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/linux-tools/3.19.0-20-lowlatency/../../linux-lts-vivid-tools-3.19.0-20/cpupower