### 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

"amount              (numeric) The total amount in " + CURRENCY_UNIT + " received for this wallet.\n"
                },
                RPCExamples{
            "\nThe total amount in the wallet with 1 or more confirmations\n"
            + HelpExampleCli("getbalance", "") +
            "\nThe total amount in the wallet at least 6 blocks confirmed\n"
            + HelpExampleCli("getbalance", "\"*\" 6") +
            "\nAs a JSON-RPC call\n"
            + HelpExampleRpc("getbalance", "\"*\", 6")
                },
            }.Check(request);
    
    
    pwallet->BlockUntilSyncedToCurrentChain();
    auto locked_chain = pwallet->chain().lock();
    LOCK(pwallet->cs_wallet);
    const UniValue& dummy_value = request.params[0];
    if (!dummy_value.isNull() && dummy_value.get_str() != "*") {
        throw JSONRPCError(RPC_METHOD_DEPRECATED, "dummy first argument must be excluded or set to \"*\".");
    }
    int min_depth = 0;
    if (!request.params[1].isNull()) {
        min_depth = request.params[1].get_int();
    }
    bool include_watchonly = ParseIncludeWatchonly(request.params[2], *pwallet);
    bool avoid_reuse = GetAvoidReuseFlag(pwallet, request.params[3]);
    const auto bal = pwallet->GetBalance(min_depth, avoid_reuse);
    return ValueFromAmount(bal.m_mine_trusted + (include_watchonly ? bal.m_watchonly_trusted : 0));
}
static UniValue getunconfirmedbalance(const JSONRPCRequest &request)