Fix test in test_coordination.py for py3 compatibility
Fix test in test_coordination.py for py3 compatibility

This patch converts str to byte in Unit Test.

Change-Id: I800dd1c74d6417e4b1407ad2ef49576f679f7ba7

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