message: minor style change
  (replace 'LogPrintf'+'return false' with 'return error')
diff: @@ -519,11 +519,11 @@ bool CMasternodeBroadcast::CheckAndUpdate(int& nDos)
  std::string errorMessage = "";
  if (!obfuScationSigner.VerifyMessage(pubKeyCollateralAddress, sig, GetNewStrMessage(), errorMessage)
  - && !obfuScationSigner.VerifyMessage(pubKeyCollateralAddress, sig, GetOldStrMessage(), errorMessage)) {
  - LogPrintf("CMasternodeBroadcast::CheckAndUpdate - Got bad Masternode address signature\n");
  + && !obfuScationSigner.VerifyMessage(pubKeyCollateralAddress, sig, GetOldStrMessage(), errorMessage))
  + {
  // don't ban for old masternodes, their sigs could be broken because of the bug
  nDos = protocolVersion < MIN_PEER_MNANNOUNCE ? 0 : 100;
  - return false;
  + return error("CMasternodeBroadcast::CheckAndUpdate - Got bad Masternode address signature : %s", errorMessage);
  }
  if (Params().NetworkID() == CBaseChainParams::MAIN) {
  