ethtool: remove some more usages

This patch continues with the removal of the python ethtool
dependency, as it is not really necessary now that the libnl
bindings are mature.

Change-Id: Ib97f8d536edf293af748f5c16316ee92f162fe5f
Signed-off-by: Antoni S. Puimedon <asegurap@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/32381
Reviewed-by: Dan Kenigsberg <danken@redhat.com>