message: PoS miner: add height to the first input scriptSig of the coinstake tx + remove unneded IncrementExtraNonce call in PoS blocks.
diff: @@ -182,6 +182,7 @@ bool SolveProofOfStake(CBlock* pblock, CBlockIndex* pindexPrev, CWallet* pwallet
  pblock->nTime = nTxNewTime;
  CMutableTransaction emptyTx;
  emptyTx.vin.resize(1);
  + emptyTx.vin[0].scriptSig = CScript() << pindexPrev->nHeight + 1 << OP_0;
  emptyTx.vout.resize(1);
  emptyTx.vout[0].SetEmpty();
  pblock->vtx.emplace_back(emptyTx);
  @@ -446,8 +447,7 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn, CWallet* pwallet,
  pblocktemplate->vTxSigOps[0] = GetLegacySigOpCount(pblock->vtx[0]);
  if (fProofOfStake) {
  - unsigned int nExtraNonce = 0;
  - IncrementExtraNonce(pblock, pindexPrev, nExtraNonce);
  + pblock->hashMerkleRoot = BlockMerkleRoot(*pblock);
  LogPrintf("CPUMiner : proof-of-stake block found %s \n", pblock->GetHash().GetHex());
  if (!SignBlock(*pblock, *pwallet)) {
  LogPrintf("%s: Signing new block with UTXO key failed \n", __func__);
  