message: Clean up the requesting of a dsproof via and INV message
  There was some hacky code put in to account for a new INV double spend
  proof message type which was cleaned up here.
diff: @@ -1026,7 +1026,7 @@ bool ProcessMessage(CNode *pfrom, std::string strCommand, CDataStream &vRecv, in
  inv.hash.ToString(), fAlreadyHaveBlock, fImporting, fReindex, IsChainNearlySyncd());
  }
  }
  - else // If we get here then inv.type must == MSG_TX or MSG_DOUBLESPENDPROOF
  + else if (inv.type == MSG_TX)
  {
  bool fAlreadyHaveTx = TxAlreadyHave(inv);
  // LOG(NET, "got inv: %s %d peer=%s\n", inv.ToString(), fAlreadyHaveTx ? "have" : "new",
  @@ -1044,18 +1044,15 @@ bool ProcessMessage(CNode *pfrom, std::string strCommand, CDataStream &vRecv, in
  // transaction volumes increase.
  else if (!fAlreadyHaveTx && !IsInitialBlockDownload())
  {
  - if (inv.type == MSG_DOUBLESPENDPROOF)
  + requester.AskFor(inv, pfrom);
  + }
  + }
  + else if (inv.type == MSG_DOUBLESPENDPROOF)
  {
  - // this is a bit hacky because I'm not going to find out why BU no longer supports
  - // generic INV/GETDATA pairs, as the requester.AskFor fails.
  std::vector<CInv> vGetData;
  vGetData.push_back(inv);
  pfrom->PushMessage(NetMsgType::GETDATA, vGetData);
  }
  - else
  - requester.AskFor(inv, pfrom);
  - }
  - }
  // Track requests for our stuff.
  GetMainSignals().Inventory(inv.hash);
  