message: [GUI] Custom fee, min amount validation.
diff: @@ -128,6 +128,9 @@ void SendCustomFeeDialog::accept()
  if (customFee >= insaneFee) {
  inform(tr("Fee too high. Must be below: %1").arg(
  BitcoinUnits::formatWithUnit(walletModel->getOptionsModel()->getDisplayUnit(), insaneFee)));
  + } else if (customFee < CWallet::minTxFee.GetFeePerK()) {
  + inform(tr("Fee too low. Must be above: %1").arg(
  + BitcoinUnits::formatWithUnit(walletModel->getOptionsModel()->getDisplayUnit(), CWallet::minTxFee.GetFeePerK() * 1000)));
  } else {
  walletModel->setWalletCustomFee(fUseCustomFee, customFee);
  QDialog::accept();
  