/usr/lib/x86_64-linux-gnu/libaccount-plugin-1.0.so.0 is in libaccount-plugin-1.0-0 0.1.8+16.04.20160201-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libaccount-plugin-1.0.so.0.1.0