dcos overlay test (specifically dcos_overlay_SUITE.erl) needs to be improved / rewritten.

navstar_overlay_SUITE is broken “by design”. It starts n agent nodes and each agent node creates its own vlxan. They do that on the same vm at the same time. Previously it worked because we didn’t check and remove the link. at the moment this test are testing that there is a race condition in dcos_overlay_poller between checking and creating the link. that’s why it passes sometimes.

{mesos_state_vxlaninfo,1024,<<"vtep1024">>,<<"44.128.0.1/20">>,<<"70:b3:d5:80:00:1">>}
{mesos_state_vxlaninfo,1024,<<"vtep1024">>,<<"44.128.0.2/20">>,<<"70:b3:d5:80:00:2">>}
{mesos_state_vxlaninfo,1024,<<"vtep1024">>,<<"44.128.0.3/20">>,<<"70:b3:d5:80:00:3">>}
{mesos_state_vxlaninfo,1024,<<"vtep1024">>,<<"44.128.0.4/20">>,<<"70:b3:d5:80:00:4">>}