message: Use log level NET for Invalid Message Start messages.
  These are filling up the log with ever increasing fequency with a variety
  of fake nodes out there trying to send us messages.
diff: @@ -6885,7 +6885,7 @@ bool ProcessMessages(CNode *pfrom)
  // Scan for message start
  if (memcmp(msg.hdr.pchMessageStart, pfrom->GetMagic(chainparams), MESSAGE_START_SIZE) != 0)
  {
  - LOGA("PROCESSMESSAGE: INVALID MESSAGESTART %s peer=%s\n", SanitizeString(msg.hdr.GetCommand()),
  + LOG(NET, "PROCESSMESSAGE: INVALID MESSAGESTART %s peer=%s\n", SanitizeString(msg.hdr.GetCommand()),
  pfrom->GetLogName());
  if (!pfrom->fWhitelisted)
  {
  