/usr/share/doc/openvswitch-switch-dpdk/changelog.Debian.gz is in openvswitch-switch-dpdk 2.5.5-0ubuntu0.16.04.2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/openvswitch-switch-dpdk/../openvswitch-common/changelog.Debian.gz