message: requestManager: Fix potential division by zero
  This makes the calculation of nOverallAverageResponseTime more robust.
  It looks like this can only triggered in the unlikely condition that
  nMaxOutConnections is set to zero.
  (from clang static analysis)
diff: @@ -1092,11 +1092,20 @@ bool CRequestManager::MarkBlockAsReceived(const uint256 &hash, CNode *pnode)
  uint32_t nOverallRange = blockRange * nMaxOutConnections;
  if (nIterations <= nOverallRange)
  nIterations++;
  +
  + if (nOverallRange > 0)
  + {
  if (nIterations > nOverallRange)
  {
  nOverallAverageResponseTime -= (nOverallAverageResponseTime / nOverallRange);
  }
  nOverallAverageResponseTime += nResponseTime / nOverallRange;
  + }
  + else
  + {
  + LOG(IBD, "Calculation of average response time failed and will be inaccurate due to division by "
  + "zero.\n");
  + }
  // Request for a disconnect if over the response time limit. We don't do an fDisconnect = true here
  // because we want to drain the queue for any blocks that are still returning. This prevents us from
  