Import policykit version 0.9.

Import policykit version 0.9.

PolicyKit is an application-level toolkit for defining and handling the
policy that allows unprivileged processes to speak to privileged processes:
It is a framework for centralizing the decision making process with respect
to granting access to privileged operations for unprivileged applications.
PolicyKit is specifically targeting applications in rich desktop environments
on multi-user UNIX-like operating systems. It does not imply or rely on any
exotic kernel features.