test_marathon: fix failing test caused by requests library update (#834)
test_marathon: fix failing test caused by requests library update (#834)


mesosphere/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,mesosphere/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli,dcos/dcos-cli,mesosphere/dcos-cli,dcos/dcos-cli,kensipe/dcos-cli