/usr/lib/libsignon-plugins-common.so is in signond-dev 8.56+14.04.20140307-0ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libsignon-plugins-common.so.1.0.0
/usr/lib/libsignon-plugins-common.so.1.0.0