Protocol version type safety (#2811)

* add type safety for protocol_version

* cleanup tui for protocol version

* cleanup

api/src/types.rs

@@ -74,7 +74,7 @@ pub struct Status {
 impl Status {
 	pub fn from_tip_and_peers(current_tip: chain::Tip, connections: u32) -> Status {
 		Status {
-			protocol_version: p2p::msg::PROTOCOL_VERSION,
+			protocol_version: p2p::msg::ProtocolVersion::default().into(),
 			user_agent: p2p::msg::USER_AGENT.to_string(),
 			connections: connections,
 			tip: Tip::from_tip(current_tip),