### 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

nMaximumCount = options["maximumCount"].get_int64();
    }
    
    
    pwallet->BlockUntilSyncedToCurrentChain();
    UniValue results(UniValue::VARR);
    std::vector<COutput> vecOutputs;
    {
        CCoinControl cctl;
        cctl.m_avoid_address_reuse = false;
        cctl.m_min_depth = nMinDepth;
        cctl.m_max_depth = nMaxDepth;
        auto locked_chain = pwallet->chain().lock();
        LOCK(pwallet->cs_wallet);
        pwallet->AvailableCoins(*locked_chain, vecOutputs, !include_unsafe, &cctl, nMinimumAmount, nMaximumAmount, nMinimumSumAmount, nMaximumCount);
    }
    LOCK(pwallet->cs_wallet);
    const bool avoid_reuse = pwallet->IsWalletFlagSet(WALLET_FLAG_AVOID_REUSE);
    for (const COutput& out : vecOutputs) {
        CTxDestination address;
        const CScript& scriptPubKey = out.tx->tx->vout[out.i].scriptPubKey;
        bool fValidAddress = ExtractDestination(scriptPubKey, address);
        bool reused = avoid_reuse && pwallet->IsUsedDestination(address);
        if (destinations.size() && (!fValidAddress || !destinations.count(address)))
            continue;
        UniValue entry(UniValue::VOBJ);
        entry.pushKV("txid", out.tx->GetHash().GetHex());
        entry.pushKV("vout", out.i);
        if (fValidAddress) {
            entry.pushKV("address", EncodeDestination(address));