fix broken TestConfigNetwork.testAddNetworkValidation

this was broken after http://gerrit.oveir.org/34538
was merged.

Change-Id: I14a8138b239c1275c67eba6888115d33bf596f05
Signed-off-by: ibarkan <ibarkan@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/34868
Tested-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>