relay-chain-interface: Do not depend on polkadot-service (#2287)

parachain-template/node/src/service.rs

@@ -17,7 +17,7 @@ use cumulus_client_service::{
 	start_full_node, BuildNetworkParams, StartCollatorParams, StartFullNodeParams,
 };
 use cumulus_primitives_core::ParaId;
-use cumulus_relay_chain_interface::{RelayChainError, RelayChainInterface};
+use cumulus_relay_chain_interface::RelayChainInterface;
 
 // Substrate Imports
 use frame_benchmarking_cli::SUBSTRATE_REFERENCE_HARDWARE;
@@ -162,10 +162,7 @@ async fn start_node_impl(
 		hwbench.clone(),
 	)
 	.await
-	.map_err(|e| match e {
-		RelayChainError::ServiceError(polkadot_service::Error::Sub(x)) => x,
-		s => s.to_string().into(),
-	})?;
+	.map_err(|e| sc_service::Error::Application(Box::new(e) as Box<_>))?;
 
 	let force_authoring = parachain_config.force_authoring;
 	let validator = parachain_config.role.is_authority();