tor/changes/ticket20895

  o Minor features (forward-compatibility):
    - If a relay supports some link authentication protocol that we do not
      recognize, then include that relay's ed25519 key when telling other
      relays to extend to it.  Previously, we treated future versions as if
      they were too old to support ed25519 link authentication.
      Closes ticket 20895.
Split the behavior of node_supports_ed25519_link_authentication(). Before, this function meant "can we connect to this node and authenticate it using its ed25519 key?" Now it can additionally mean, "when somebody else connects to this node, do we expect that they can authenticate using the node's ed25519 key"? This change lets us future-proof our link authentication a bit. Closes ticket 20895. No backport needed, since ed25519 link authentication support has not been in any LTS release yet, and existing releases with it should be obsolete before any releases without support for linkauth=3 are released. 2017-09-11 16:00:11 +02:00			`o Minor features (forward-compatibility):`
			`- If a relay supports some link authentication protocol that we do not`
			`recognize, then include that relay's ed25519 key when telling other`
			`relays to extend to it. Previously, we treated future versions as if`
			`they were too old to support ed25519 link authentication.`
			`Closes ticket 20895.`