eth/txpool: typo that tracker not a pool

Author: zouxyan

core/txpool/locals/tx_tracker.go

@@ -58,18 +58,18 @@ type TxTracker struct {
 
 // New creates a new TxTracker
 func New(journalPath string, journalTime time.Duration, chainConfig *params.ChainConfig, next *txpool.TxPool) *TxTracker {
-	pool := &TxTracker{
+	tracker := &TxTracker{
 		all:        make(map[common.Hash]*types.Transaction),
 		byAddr:     make(map[common.Address]*legacypool.SortedMap),
 		signer:     types.LatestSigner(chainConfig),
 		shutdownCh: make(chan struct{}),
 		pool:       next,
 	}
 	if journalPath != "" {
-		pool.journal = newTxJournal(journalPath)
-		pool.rejournal = journalTime
+		tracker.journal = newTxJournal(journalPath)
+		tracker.rejournal = journalTime
 	}
-	return pool
+	return tracker
 }
 
 // HasTx checks if TxTracker has this tx already.