multi: add SpewLogClosure to avoid code repetition

lnrpc/invoicesrpc/addinvoice.go

@@ -15,7 +15,6 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
 	"github.com/btcsuite/btcd/wire"
-	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/channeldb"
 	"github.com/lightningnetwork/lnd/channeldb/models"
 	"github.com/lightningnetwork/lnd/invoices"
@@ -474,10 +473,7 @@ func AddInvoice(ctx context.Context, cfg *AddInvoiceConfig,
 	}
 
 	log.Tracef("[addinvoice] adding new invoice %v",
-		lnutils.NewLogClosure(func() string {
-			return spew.Sdump(newInvoice)
-		}),
-	)
+		lnutils.SpewLogClosure(newInvoice))
 
 	// With all sanity checks passed, write the invoice to the database.
 	_, err = cfg.AddInvoice(ctx, newInvoice, paymentHash)