Remove --legacy-network-protocol CLI flag (#6411)

substrate/client/cli/src/params/network_params.rs

@@ -102,11 +102,6 @@ pub struct NetworkParams {
 	/// By default this option is true for `--dev` and false otherwise.
 	#[structopt(long)]
 	pub discover_local: bool,
-
-	/// Use the legacy "pre-mainnet-launch" networking protocol. Enable if things seem broken.
-	/// This option will be removed in the future.
-	#[structopt(long)]
-	pub legacy_network_protocol: bool,
 }
 
 impl NetworkParams {
@@ -165,7 +160,6 @@ impl NetworkParams {
 			},
 			max_parallel_downloads: self.max_parallel_downloads,
 			allow_non_globals_in_dht: self.discover_local || is_dev,
-			use_new_block_requests_protocol: !self.legacy_network_protocol,
 		}
 	}
 }