[Libvir] PATCH: Don't request polkit auth if client is root

[Jim Meyering]

"Daniel P. Berrange" <berrange at redhat.com> wrote:
> This patch makes two adjustments to the way policy kit authentication is
> done.
>
>  - Currently the server unconditionally ask the client to do policykit
>    authentication. This is unnecessary if the remote client is running
>    as root, which we can check via UNIX socket credentials. Unconditionally
>    asking plays havoc with SSH tunneling, so this patch makes it check the
>    socket credentials &not ask for auth if the client is UID==0
>
>  - The virsh client will unconditionally call polkit-auth to request
>    credentials. This is also unneccessary if the client is running as
>    root, so this patch makes it skip that step as root.
>
> The patch is bigger than it seems because removing an if() conditional
> made a huge chunk be re-indented.

Good idea.  Looks fine.
ACK.

[BTW, thanks for the SO_PEERCRED example -- I didn't know about it,
 and was surprised to find so little documentation on it. ]