message: Actually only use filterInventoryKnown with MSG_TX inventory messages.
  Previously this logic could erroneously filter a MSG_BLOCK inventory message.
diff: @@ -6397,7 +6397,7 @@ bool SendMessages(CNode* pto)
  vInv.reserve(pto->vInventoryToSend.size());
  vInvWait.reserve(pto->vInventoryToSend.size());
  for (const CInv& inv : pto->vInventoryToSend) {
  - if (pto->filterInventoryKnown.contains(inv.hash))
  + if (inv.type == MSG_TX && pto->filterInventoryKnown.contains(inv.hash))
  continue;
  // trickle out tx inv to protect privacy
  @@ -6416,15 +6416,14 @@ bool SendMessages(CNode* pto)
  }
  }
  - if (!pto->filterInventoryKnown.contains(inv.hash)) {
  pto->filterInventoryKnown.insert(inv.hash);
  +
  vInv.push_back(inv);
  if (vInv.size() >= 1000) {
  pto->PushMessage(NetMsgType::INV, vInv);
  vInv.clear();
  }
  }
  - }
  pto->vInventoryToSend = vInvWait;
  }
  if (!vInv.empty())
  