Don't override log context set by inner WithContexts

If a logger is wrapped with `WithContext` which is then wrapped
with another `WithContext` with different values, we want to use
the context information set closest to the code, ie that which
will be set first.

Thus, here, we avoid overriding context that has already been set.

Author: TheBlueMatt

lightning/src/util/logger.rs

@@ -314,16 +314,16 @@ where
 	L::Target: Logger,
 {
 	fn log(&self, mut record: Record) {
-		if self.peer_id.is_some() {
+		if self.peer_id.is_some() && record.peer_id.is_none() {
 			record.peer_id = self.peer_id
 		};
-		if self.channel_id.is_some() {
+		if self.channel_id.is_some() && record.channel_id.is_none() {
 			record.channel_id = self.channel_id;
 		}
-		if self.payment_hash.is_some() {
+		if self.payment_hash.is_some() && record.payment_hash.is_none() {
 			record.payment_hash = self.payment_hash;
 		}
-		if self.payment_id.is_some() {
+		if self.payment_id.is_some() && record.payment_id.is_none() {
 			record.payment_id = self.payment_id;
 		}
 		self.logger.log(record)