eth: delete unused RpcServer field

eth/backend.go

@@ -20,7 +20,6 @@ import (
 	"github.com/ethereum/go-ethereum/p2p"
 	"github.com/ethereum/go-ethereum/p2p/discover"
 	"github.com/ethereum/go-ethereum/p2p/nat"
-	"github.com/ethereum/go-ethereum/rpc"
 	"github.com/ethereum/go-ethereum/whisper"
 )
 
@@ -124,8 +123,6 @@ type Ethereum struct {
 	blockSub event.Subscription
 	miner    *miner.Miner
 
-	RpcServer rpc.RpcServer
-
 	logger logger.LogSystem
 
 	Mining  bool
@@ -268,10 +265,6 @@ func (s *Ethereum) Stop() {
 	s.txSub.Unsubscribe()    // quits txBroadcastLoop
 	s.blockSub.Unsubscribe() // quits blockBroadcastLoop
 
-	if s.RpcServer != nil {
-		s.RpcServer.Stop()
-	}
-
 	s.txPool.Stop()
 	s.eventMux.Stop()
 	s.blockPool.Stop()