ethstats: Fix ethstats reporting while syncing

ethstats/ethstats.go

@@ -613,6 +613,7 @@ func (s *Service) reportHistory(conn *websocket.Conn, list []uint64) error {
 		}
 		// Ran out of blocks, cut the report short and send
 		history = history[len(history)-i:]
+		break
 	}
 	// Assemble the history report and send it to the server
 	if len(history) > 0 {