Avoid overloading introduction_node_id

Author: jkczyz

lightning/src/onion_message/messenger.rs

@@ -319,8 +319,8 @@ where
 
 		let blinding_secret_bytes = self.entropy_source.get_secure_random_bytes();
 		let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
-		let (introduction_node_id, blinding_point) = if intermediate_nodes.len() != 0 {
-			(intermediate_nodes[0], PublicKey::from_secret_key(&self.secp_ctx, &blinding_secret))
+		let (first_node_id, blinding_point) = if let Some(node_id) = intermediate_nodes.first() {
+			(*node_id, PublicKey::from_secret_key(&self.secp_ctx, &blinding_secret))
 		} else {
 			match destination {
 				Destination::Node(pk) => (pk, PublicKey::from_secret_key(&self.secp_ctx, &blinding_secret)),
@@ -337,8 +337,8 @@ where
 			packet_payloads, packet_keys, prng_seed).map_err(|()| SendError::TooBigPacket)?;
 
 		let mut pending_per_peer_msgs = self.pending_messages.lock().unwrap();
-		if outbound_buffer_full(&introduction_node_id, &pending_per_peer_msgs) { return Err(SendError::BufferFull) }
-		match pending_per_peer_msgs.entry(introduction_node_id) {
+		if outbound_buffer_full(&first_node_id, &pending_per_peer_msgs) { return Err(SendError::BufferFull) }
+		match pending_per_peer_msgs.entry(first_node_id) {
 			hash_map::Entry::Vacant(_) => Err(SendError::InvalidFirstHop),
 			hash_map::Entry::Occupied(mut e) => {
 				e.get_mut().push_back(msgs::OnionMessage { blinding_point, onion_routing_packet });