update web3 transaction hash from RLP (#250)

* remove ethereum hash of web3 transaction type (always amino hash)

* Update changelog

x/evm/handler.go

@@ -43,7 +43,8 @@ func HandleMsgEthereumTx(ctx sdk.Context, k Keeper, msg types.MsgEthereumTx) sdk
 		return sdk.ResultFromError(err)
 	}
 
-	txHash := msg.Hash()
+	txHash := tmtypes.Tx(ctx.TxBytes()).Hash()
+	ethHash := common.BytesToHash(txHash)
 
 	st := types.StateTransition{
 		Sender:       sender,
@@ -55,12 +56,13 @@ func HandleMsgEthereumTx(ctx sdk.Context, k Keeper, msg types.MsgEthereumTx) sdk
 		Payload:      msg.Data.Payload,
 		Csdb:         k.CommitStateDB.WithContext(ctx),
 		ChainID:      intChainID,
-		THash:        &txHash,
+		THash:        &ethHash,
 		Simulate:     ctx.IsCheckTx(),
 	}
+
 	// Prepare db for logs
 	// TODO: block hash
-	k.CommitStateDB.Prepare(txHash, txHash, k.TxCount)
+	k.CommitStateDB.Prepare(ethHash, common.Hash{}, k.TxCount)
 	k.TxCount++
 
 	// TODO: move to keeper

x/evm/types/msg.go

@@ -198,18 +198,6 @@ func (msg *MsgEthereumTx) DecodeRLP(s *rlp.Stream) error {
 	return err
 }
 
-// Hash hashes the RLP encoding of a transaction.
-func (msg *MsgEthereumTx) Hash() ethcmn.Hash {
-	if hash := msg.hash.Load(); hash != nil {
-		return hash.(ethcmn.Hash)
-	}
-
-	v := rlpHash(msg)
-	msg.hash.Store(v)
-
-	return v
-}
-
 // Sign calculates a secp256k1 ECDSA signature and signs the transaction. It
 // takes a private key and chainID to sign an Ethereum transaction according to
 // EIP155 standard. It mutates the transaction as it populates the V, R, S

x/evm/types/msg_test.go

@@ -89,14 +89,6 @@ func TestMsgEthereumTxRLPDecode(t *testing.T) {
 	require.Equal(t, expectedMsg.Data, msg.Data)
 }
 
-func TestMsgEthereumTxHash(t *testing.T) {
-	addr := ethcmn.BytesToAddress([]byte("test_address"))
-	msg := NewMsgEthereumTx(0, &addr, nil, 100000, nil, []byte("test"))
-
-	hash := msg.Hash()
-	require.Equal(t, "E2AA2E68E7586AE9700F1D3D643330866B6AC2B6CA4C804F7C85ECB11D0B0B29", fmt.Sprintf("%X", hash))
-}
-
 func TestMsgEthereumTxSig(t *testing.T) {
 	chainID := big.NewInt(3)