Fixed WAL gc age bug

lib/rep/replicator-walgc.go

@@ -15,7 +15,7 @@ func (rep *Replicator) runWALGC() {
 		select {
 		case <-ticker.C:
 			state := rep.getState()
-			before := time.Now().Unix() - rep.conf.WALSegMaxAgeSec
+			before := time.Now().Unix() - rep.conf.WALSegGCAgeSec
 			if err := rep.wal.DeleteBefore(before, state.SeqNum); err != nil {
 				log.Printf("[WAL-GC] failed to delete wal segments: %v", err)
 			}