message: Fix not enough fee when mint change is exact
diff: @@ -3862,7 +3862,7 @@ bool CWallet::CreateZerocoinMintTransaction(const CAmount nValue, CMutableTransa
  CAmount nValueRemaining = 0;
  while (true) {
  //mint a coin with the closest denomination to what is being requested
  - nFeeRet = txNew.vout.size() * Params().Zerocoin_MintFee();
  + nFeeRet = max(static_cast<int>(txNew.vout.size()), 1) * Params().Zerocoin_MintFee();
  nValueRemaining = nValue - nMintingValue - (isZCSpendChange ? nFeeRet : 0);
  // if this is change of a zerocoinspend, then we can't mint all change, at least something must be given as a fee
  