ethtool: remove vdsm dependency on ethtool

We only leave a dependency in the bootstrap package as it is
deprecated anyway and touching it would do more harm than good.

Change-Id: I71f97e182f3fc74cfa9e8288b1071aad1082fb6f
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/32382
Reviewed-by: Dan Kenigsberg <danken@redhat.com>