message: don't mint while sync is not finished
diff: @@ -5232,6 +5232,7 @@ void BitcoinMiner(CWallet *pwallet, bool fProofOfStake)
  unsigned int nExtraNonce = 0;
  string strMintMessage = _("Info: Minting suspended due to locked wallet.");
  + string strMintSyncMessage = _("Info: Minting suspended while synchronizing wallet.");
  string strMintDisabledMessage = _("Info: Minting disabled by 'nominting' option.");
  string strMintBlockMessage = _("Info: Minting suspended due to block creation failure.");
  @@ -5245,6 +5246,12 @@ void BitcoinMiner(CWallet *pwallet, bool fProofOfStake)
  while (vNodes.empty())
  MilliSleep(1000);
  + while (Checkpoints::GuessVerificationProgress(pindexBest)<0.99999)
  + {
  + strMintWarning = strMintSyncMessage;
  + MilliSleep(10000);
  + }
  +
  while (pwallet->IsLocked())
  {
  strMintWarning = strMintMessage;
  