Fixes permissions and owner for undercloud.qcow2

The undercloud storage disk is copied during our deployment from
modified underloud from upstream.  We copy it as owner root with wrong
permissions.  This changes the owner to qemu and sets the permissions
the same as the other storage disks that virsh creates for overcloud
nodes.

Change-Id: Ie884a586f91be3461e4b511e224d061639f04c69
Signed-off-by: Tim Rozet <trozet@redhat.com>