message: fix nTxOffset in stake generation
diff: @@ -4364,7 +4364,7 @@ bool CWallet::CreateCoinStake(const CKeyStore& keystore, unsigned int nBits, int
  // Search nSearchInterval seconds back up to nMaxStakeSearchInterval
  uint256 hashProofOfStake = uint256();
  COutPoint prevoutStake = pcoin.outpoint;
  - if (CheckStakeKernelHash(nBits, chainActive.Tip(), header, postx.nTxOffset + sizeof(CBlockHeader), tx, prevoutStake, txNew.nTime - n, hashProofOfStake))
  + if (CheckStakeKernelHash(nBits, chainActive.Tip(), header, postx.nTxOffset + CBlockHeader::NORMAL_SERIALIZE_SIZE, tx, prevoutStake, txNew.nTime - n, hashProofOfStake))
  {
  // Found a kernel
  if (gArgs.GetBoolArg("-debug", false) && gArgs.GetBoolArg("-printcoinstake", false))
  