Fix map_err lint

Use inspect_err where map_err is unnecessary.

Author: arik-so

lightning/src/ln/channelmanager.rs

@@ -4137,10 +4137,9 @@ where
 		let (onion_packet, htlc_msat, htlc_cltv) = onion_utils::create_payment_onion(
 			&self.secp_ctx, &path, &session_priv, total_value, recipient_onion, cur_height,
 			payment_hash, keysend_preimage, prng_seed
-		).map_err(|e| {
+		).inspect_err(|e| {
 			let logger = WithContext::from(&self.logger, Some(path.hops.first().unwrap().pubkey), None, Some(*payment_hash));
 			log_error!(logger, "Failed to build an onion for path for payment hash {}", payment_hash);
-			e
 		})?;
 
 		let err: Result<(), _> = loop {

lightning/src/ln/outbound_payment.rs

@@ -770,7 +770,7 @@ impl OutboundPayments {
 		let onion_session_privs = self.add_new_pending_payment(payment_hash, recipient_onion.clone(), payment_id, None, route, None, None, entropy_source, best_block_height)?;
 		self.pay_route_internal(route, payment_hash, &recipient_onion, None, payment_id, None,
 			onion_session_privs, node_signer, best_block_height, &send_payment_along_path)
-			.map_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); e })
+			.inspect_err(|e| { self.remove_outbound_if_all_failed(payment_id, &e); })
 	}
 
 	pub(super) fn send_spontaneous_payment<R: Deref, ES: Deref, NS: Deref, IH, SP, L: Deref>(