### 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

}
    UniValue sendTo = request.params[1].get_obj();
    mapValue_t mapValue;
    if (!request.params[3].isNull() && !request.params[3].get_str().empty())
        mapValue["comment"] = request.params[3].get_str();
    UniValue subtractFeeFromAmount(UniValue::VARR);
    if (!request.params[4].isNull())
        subtractFeeFromAmount = request.params[4].get_array();
    CCoinControl coin_control;
    if (!request.params[5].isNull()) {
        coin_control.m_signal_bip125_rbf = request.params[5].get_bool();
    }
    if (!request.params[6].isNull()) {
        coin_control.m_confirm_target = ParseConfirmTarget(request.params[6], pwallet->chain().estimateMaxBlocks());
    }
    if (!request.params[7].isNull()) {
        if (!FeeModeFromString(request.params[7].get_str(), coin_control.m_fee_mode)) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid estimate_mode parameter");
        }
    }
    std::set<CTxDestination> destinations;
    std::vector<CRecipient> vecSend;
    std::vector<std::string> keys = sendTo.getKeys();
    for (const std::string& name_ : keys) {
        CTxDestination dest = DecodeDestination(name_);
        if (!IsValidDestination(dest)) {
            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, std::string("Invalid Bitcoin address: ") + name_);
        }
        if (destinations.count(dest)) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, std::string("Invalid parameter, duplicated address: ") + name_);