[ACS4.4] Cherry-pick 356f6121a78d147d72136044c90472234f667730

[Min Chen]

Hi Daan,

        Can you please cherry-pick this commit from 4.4-forward to 4.4?

        Commit: 356f6121a78d147d72136044c90472234f667730
        CLOUDSTACK-6742: listVolumes - As regularuser , able to list Vms and
volumes of other users.

        Thanks
        -min