message: [Consensus] Reject old message versions for CSporkMessage
  Reject old messages 600 blocks after enforcement
diff: @@ -91,6 +91,20 @@ void CSporkManager::ProcessSpork(CNode* pfrom, std::string& strCommand, CDataStr
  return;
  }
  + // reject old signatures 600 blocks after hard-fork
  + if (spork.nMessVersion != MessageVersion::MESS_VER_HASH) {
  + int nHeight;
  + {
  + LOCK(cs_main);
  + nHeight = chainActive.Height();
  + }
  + if (Params().NewSigsActive(nHeight - 600)) {
  + LogPrintf("%s : nMessVersion=%d not accepted anymore at block %d", __func__, spork.nMessVersion, nHeight);
  + return;
  + }
  + }
  +
  +
  uint256 hash = spork.GetHash();
  {
  LOCK(cs);
  