message: Allow anon coin stake only after V3 fork time
diff: @@ -853,6 +853,9 @@ bool CheckAnonProofOfStake(CBlockIndex* pindexPrev, const CTransaction& tx, unsi
  if (!tx.IsAnonCoinStake())
  return error("CheckAnonProofOfStake() : called on non-anon-coinstake %s", tx.GetHash().ToString());
  + if (!Params().IsForkV3(tx.nTime))
  + return error("CheckAnonProofOfStake() : called before V3 fork time with anon-coinstake %s", tx.GetHash().ToString());
  +
  CTxDB txdb("r");
  // Kernel (input 0) must match the stake hash target per coin age (nBits)
  