order: fix concurrent map access

Because spew.Sdump will iterate through the whole struct, it will also
access maps, such as the underlying sync.Map. Which can then lead to
concurrent map access, because that access isn't protected by the mutex.

Author: guggero

Diff for: rfq/order.go

@@ -912,9 +912,21 @@ func (h *OrderHandler) fetchPolicy(htlc lndclient.InterceptedHtlc) (Policy,
 	inPolicy, haveInPolicy := h.policies.Load(inScid)
 
 	log.Tracef("Have inbound policy: %v: %v", haveInPolicy,
-		spew.Sdump(inPolicy))
-	log.Tracef("Have outbound policy: %v: %v", haveOutPolicy,
-		spew.Sdump(outPolicy))
+		lnutils.LogClosure(func() string {
+			if inPolicy == nil {
+				return "<nil>"
+			}
+
+			return fmt.Sprintf("%d", inPolicy.Scid())
+		}))
+	log.Tracef("Have outbound policy: %v: scid %v", haveOutPolicy,
+		lnutils.LogClosure(func() string {
+			if outPolicy == nil {
+				return "<nil>"
+			}
+
+			return fmt.Sprintf("%d", outPolicy.Scid())
+		}))
 
 	var (
 		foundPolicy *Policy