Remove hack around secondary connections handshakes (#7246)

substrate/client/network/src/protocol/generic_proto/behaviour.rs

@@ -1312,30 +1312,11 @@ impl NetworkBehaviour for GenericProto {
 					self.events.push_back(NetworkBehaviourAction::GenerateEvent(event));
 
 				} else {
-					// In normal situations, the handshake is supposed to be a Status message, and
-					// we would discard Status messages received from secondary connections.
-					// However, in Polkadot 0.8.10 and below, nodes don't send a Status message
-					// when opening secondary connections and instead directly consider the
-					// substream as open. When connecting to such a node, the first message sent
-					// by the remote will always be considered by our local node as the handshake,
-					// even when it is a regular message.
-					// In order to maintain backwards compatibility, we therefore report the
-					// handshake as if it was a regular message, and the upper layer will ignore
-					// any superfluous Status message.
-					// The code below should be removed once Polkadot 0.8.10 and below are no
-					// longer widely in use, and should be replaced with simply printing a log
-					// entry.
 					debug!(
 						target: "sub-libp2p",
 						"Handler({:?}) => Secondary connection opened custom protocol",
 						source
 					);
-					trace!(target: "sub-libp2p", "External API <= Message({:?})", source);
-					let event = GenericProtoOut::LegacyMessage {
-						peer_id: source,
-						message: From::from(&received_handshake[..]),
-					};
-					self.events.push_back(NetworkBehaviourAction::GenerateEvent(event));
 				}
 			}