message: fix eth_call
diff: @@ -201,8 +201,14 @@ func (e *EthCallMethodHandler) cacheKey(req *RPCReq) string {
  if err := json.Unmarshal(input[0], &params); err != nil {
  return ""
  }
  + if params.From != "" || params.Gas != "" {
  + return ""
  + }
  + if params.Value != "" && params.Value != "0x0" {
  + return ""
  + }
  // ensure the order is consistent
  - keyParams := fmt.Sprintf("%s:%s:%s:%s:%s:%s", params.From, params.To, params.Gas, params.GasPrice, params.Value, params.Data)
  + keyParams := fmt.Sprintf("%s:%s", params.To, params.Data)
  return fmt.Sprintf("method:eth_call:%s", keyParams)
  }
  