conditionally run sudo -u vdsm dd
conditionally run sudo -u vdsm dd

Run with sudo -u vdsm only if it's not running as the vdsm user.

Change-Id: I544b2e296cb85b501a26ef5d7e022173a4b0a7d1
Bug-Url: https://bugzilla.redhat.com/1398443
Signed-off-by: Simone Tiraboschi <cb03129c66ba4da7ba7044049d0f43907bf857bb@redhat.com>

oVirt/ovirt-hosted-engine-ha,oVirt/ovirt-hosted-engine-ha,oVirt/ovirt-hosted-engine-ha,oVirt/ovirt-hosted-engine-ha