Add Linux reuse port

[sleipnir]

This change fix the https://github.com/bitwalker/libcluster/issues/184

This PR worked in conjunction with the following Gossip strategy setups:

defp get_gossip_strategy do
    [
      proxy: [
        strategy: Cluster.Strategy.Gossip,
        config: [
          reuseaddr: true,
          multicast_addr: "255.255.255.255",
          broadcast_only: true
        ]
      ]
    ]
  end

The image below shows my system connected to two Nodes after changing the PR and settings. Using the settings in the current version has not been shown to have any effect. In other words, only with the PR change did the system reconnect again.