message: Fix compile warning in bitcoin-miner.cpp
diff: @@ -332,13 +332,13 @@ static UniValue CpuMineBlock(unsigned int searchDuration, const UniValue &params
  found = CpuMineBlockHasher(&header, coinbaseBytes, merkleproof, randFunc);
  }
  - const auto nChecked = header.nNonce - startNonce;
  + const uint32_t nChecked = header.nNonce - startNonce;
  // Leave if not found:
  if (!found)
  {
  - const auto elapsed = GetTimeMillis() - start;
  - printf("Checked %d possibilities in %lld secs, %3.3f MH/s\n", nChecked, elapsed / 1000,
  + const int64_t elapsed = GetTimeMillis() - start;
  + printf("Checked %d possibilities in %ld secs, %3.3f MH/s\n", nChecked, elapsed / 1000,
  (nChecked / 1e6) / (elapsed / 1e3));
  return ret;
  }
  