message: Return the sender as default refund sender
diff: @@ -46,13 +46,13 @@ class QtumTransaction : public dev::eth::Transaction{
  public:
  - QtumTransaction() : nVout(0) {}
  + QtumTransaction() : nVout(0), hasRefundSender(false) {}
  QtumTransaction(dev::u256 const& _value, dev::u256 const& _gasPrice, dev::u256 const& _gas, dev::bytes const& _data, dev::u256 const& _nonce = dev::Invalid256):
  - dev::eth::Transaction(_value, _gasPrice, _gas, _data, _nonce) {}
  + dev::eth::Transaction(_value, _gasPrice, _gas, _data, _nonce) , nVout(0), hasRefundSender(false) {}
  QtumTransaction(dev::u256 const& _value, dev::u256 const& _gasPrice, dev::u256 const& _gas, dev::Address const& _dest, dev::bytes const& _data, dev::u256 const& _nonce = dev::Invalid256):
  - dev::eth::Transaction(_value, _gasPrice, _gas, _dest, _data, _nonce) {}
  + dev::eth::Transaction(_value, _gasPrice, _gas, _dest, _data, _nonce) , nVout(0), hasRefundSender(false) {}
  void setHashWith(const dev::h256 hash) { m_hashWith = hash; }
  @@ -69,14 +69,15 @@ public:
  return version;
  }
  - void setRefundSender(const dev::Address _refundSender) { refundSender = _refundSender; }
  + void setRefundSender(const dev::Address _refundSender) { refundSender = _refundSender; hasRefundSender = true;}
  - dev::Address getRefundSender() const { return refundSender; }
  + dev::Address getRefundSender() const { return hasRefundSender ? refundSender : sender();}
  private:
  uint32_t nVout;
  VersionVM version;
  dev::Address refundSender;
  + bool hasRefundSender;
  };
  #endif
  