/usr/lib/libaccount-plugin-1.0.so is in libaccount-plugin-1.0-dev 0.1.7~+14.04.20140211.2-0ubuntu4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libaccount-plugin-1.0.so.0.0.0
/usr/lib/libaccount-plugin-1.0.so.0.0.0