Differentiate invalid hmac log messages

To make it clear whether validation failed for a failure or a fulfill.

Author: joostjager

lightning/src/ln/onion_utils.rs

@@ -1235,7 +1235,7 @@ where
 
 							log_debug!(
 								logger,
-								"Invalid HMAC in attribution data for node at pos {}",
+								"Invalid failure HMAC in attribution data for node at pos {}",
 								route_hop_idx
 							);
 						},