message: Fixed bug in sigma spend tx creation
diff: @@ -1005,6 +1005,8 @@ int CSigmaState::GetCoinSetForSpend(
  uint256& blockHash_out,
  std::vector<sigma::PublicCoin>& coins_out) {
  + coins_out.clear();
  +
  pair<sigma::CoinDenomination, int> denomAndId = std::make_pair(denomination, coinGroupID);
  if (coinGroups.count(denomAndId) == 0)
  