### 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

{
            RPCHelpMan{"listwalletdir",
                "Returns a list of wallets in the wallet directory.\n",
                {},
                RPCResult{
            "{\n"
            "  \"wallets\" : [                (json array of objects)\n"
            "    {\n"
            "      \"name\" : \"name\"          (string) The wallet name\n"
            "    }\n"
            "    ,...\n"
            "  ]\n"
            "}\n"
                },
                RPCExamples{
                    HelpExampleCli("listwalletdir", "")
            + HelpExampleRpc("listwalletdir", "")
                },
            }.Check(request);
    UniValue wallets(UniValue::VARR);
    for (const auto& path : ListWalletDir()) {
        UniValue wallet(UniValue::VOBJ);
        wallet.pushKV("name", path.string());
        wallets.push_back(wallet);
    }
    UniValue result(UniValue::VOBJ);
    result.pushKV("wallets", wallets);
    return result;
}
static UniValue listwallets(const JSONRPCRequest& request)