ipwrapper: add support for veth NICs

Update ipwrapper to consider veth NICs as FakeNICs in the same
way it does with dummy NICs. This change is required for the
testSetupNetworksAddDelDhcp functional test.

Change-Id: Ifc85a1d4c81b270025916b6bc650aa382fbb37ce
Signed-off-by: Petr Benas <pbenas@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/21381
Reviewed-by: Antoni Segura Puimedon <asegurap@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>