core: set the state for the managed tx state

Set the state for the managed tx state instead of creating a new
managed state.

core/chain_manager.go

@@ -576,7 +576,7 @@ func (self *ChainManager) InsertChain(chain types.Blocks) error {
 				})
 
 				self.setTransState(state.New(block.Root(), self.stateDb))
-				self.setTxState(state.New(block.Root(), self.stateDb))
+				self.txState.SetState(state.New(block.Root(), self.stateDb))
 
 				queue[i] = ChainEvent{block, logs}
 				queueEvent.canonicalCount++