…or name collision avoidance

- The current name collision avoidance uses the requests address, which could very likely be the same for all clients
  as they could be being routed through a HTTP proxy (or two) so that is not a good disambiguator
- We use a digest of the client's interfaces and MAC addresses and the remoteFSRoot to try and give a consistent ID
- We ALWAYS append the ID if we have it as otherwise during reconnect the slaves with the same name will shuffle around
  which defeats a lot of the login that Jenkins has internally based on slaves having a consistent name
- In the event of legacy clients that do not have the ID we will let them connect with their name as long as there
  is no online slave with that name. This does mean that where there are multiple legacy swarm clients with the
  same name, only one can be on-line at any moment in time, but that is an improvement on the current where
  once a shuffle starts, none can stay on-line

…p growing