### Describe the issue

Testing in bitcoin 0.13.0, calling `bitcoin-cli listsinceblock x` is outputting all double-spent transactions that are in the wallet, even those that were double-spent well and truly before x.
### Is the issue reproducible?

Yes
#### List steps to reproduce below:
1.   Create a double-spend send to your wallet (easiest using bip125)
2.   Wait until one confirms, and then wait a few more blocks
3.   Run `bitcoin-cli listsinceblock $(bitcoin-cli getbestblockhash)` and it will output the double spent transaction
### Expected behavior

The double-spent transaction that was conflicted before the block hash should be filtered

{
    std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    CWallet* const pwallet = wallet.get();
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
            RPCHelpMan{"getaddressesbylabel",
                "\nReturns the list of addresses assigned the specified label.\n",
                {
                    {"label", RPCArg::Type::STR, RPCArg::Optional::NO, "The label."},
                },
                RPCResult{
            "{ (json object with addresses as keys)\n"
            "  \"address\": { (json object with information about address)\n"
            "    \"purpose\": \"string\" (string)  Purpose of address (\"send\" for sending address, \"receive\" for receiving address)\n"
            "  },...\n"
            "}\n"
                },
                RPCExamples{