use super instead of direct parent call for NIC

Super allows us to call parent class without having to specify
its name, simplifying further moving of the class and possibly
more inheritance.

Change-Id: Ifc30c816be7e7ef91b921477519cefc11aa76cd6
Signed-off-by: Martin Polednik <mpolednik@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/32400
Reviewed-by: Francesco Romani <fromani@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>