message: do not penalize peer for his first batch of headers
diff: @@ -3222,7 +3222,7 @@ bool ProcessNewBlockHeaders(uint32_t& nPoSTemperature, const uint256& lastAccept
  LOCK(cs_main);
  int nCooling = POW_HEADER_COOLING;
  - if (headers[0].hashPrevBlock != lastAcceptedHeader) {
  + if (headers[0].hashPrevBlock != lastAcceptedHeader && !lastAcceptedHeader.IsNull()) {
  nPoSTemperature += nCooling;
  nCooling = 0;
  }
  