message: Reject spending immature coinstake coin
diff: @@ -1517,7 +1517,7 @@ bool CheckTxInputs(const CTransaction& tx, CValidationState& state, const CCoins
  assert(coins);
  // If prev is coinbase, check that it's matured
  - if (coins->IsCoinBase()) {
  + if (coins->IsCoinBase() || coins->IsCoinStake()) {
  if (nSpendHeight - coins->nHeight < COINBASE_MATURITY)
  return state.Invalid(false,
  REJECT_INVALID, "bad-txns-premature-spend-of-coinbase",
  