Investigate registrator state corruption bug when consul agent is down

[michal-franc]

Related to:
When a consul-agent collocated with registrator has died and a container was created on this same instance. We ended up with a corrupted registrator state that was registering phantom services to consul-cluster. Manual de-register was not helping as registrator was bringing phantom service back. Only recycling registrator on that instance helped.

Check internal - postmortem from 18.06.19.

Scenario 1:

• registrator, consul-agent on one node
• kill consul-agent
• create container on that node
• check if registrator internal state has been changed
• start consul-agent
• correct service should be registered with consul

Scenario 2:

• registrator, consul-agent on one node
• kill consul-agent
• create container on that node
• destroy container on that node
• check if registrator internal state has been changed
• start consul-agent
• no service should be added to consul