Only print flake8 table if there is results
Only print flake8 table if there is results

Change-Id: I1496280ff5003d507751f04a06b08942c89539da

openstack/designate,muraliselva10/designate,tonyli71/designate,cneill/designate-testing,cneill/designate-testing,muraliselva10/designate,ramsateesh/designate,ramsateesh/designate,tonyli71/designate,tonyli71/designate,openstack/designate,grahamhayes/designate,ionrock/designate,muraliselva10/designate,grahamhayes/designate,grahamhayes/designate,ionrock/designate,openstack/designate,ramsateesh/designate,ionrock/designate,cneill/designate-testing