### 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

"\nGet detailed information about in-wallet transaction <txid>\n",
                {
                    {"txid", RPCArg::Type::STR, RPCArg::Optional::NO, "The transaction id"},
                    {"include_watchonly", RPCArg::Type::BOOL,  "true for watch-only wallets, otherwise false",
                            "Whether to include watch-only addresses in balance calculation and details[]"},
                    {"verbose", RPCArg::Type::BOOL,  "false",
                            "Whether to include a `decoded` field containing the decoded transaction (equivalent to RPC decoderawtransaction)"},
                },
                RPCResult{
            "{\n"
            "    \"amount\" : x.xxx,        (numeric) The transaction amount in " + CURRENCY_UNIT + "\n"
            "    \"fee\": x.xxx,            (numeric) The amount of the fee in " + CURRENCY_UNIT + ". This is negative and only available for the \n"
            "                              'send' category of transactions.\n"
            + TransactionDescriptionString()
            + "    \"details\" : [\n"
            "      {\n"
            "        \"involvesWatchonly\": xxx,         (bool) Only returns true if imported addresses were involved in transaction.\n"
            "        \"address\" : \"address\",          (string) The bitcoin address involved in the transaction\n"
            "        \"category\" :                      (string) The transaction category.\n"
            "                     \"send\"                  Transactions sent.\n"
            "                     \"receive\"               Non-coinbase transactions received.\n"
            "                     \"generate\"              Coinbase transactions received with more than 100 confirmations.\n"
            "                     \"immature\"              Coinbase transactions received with 100 or fewer confirmations.\n"
            "                     \"orphan\"                Orphaned coinbase transactions received.\n"
            "        \"amount\" : x.xxx,                 (numeric) The amount in " + CURRENCY_UNIT + "\n"
            "        \"label\" : \"label\",              (string) A comment for the address/transaction, if any\n"
            "        \"vout\" : n,                       (numeric) the vout value\n"
            "        \"fee\": x.xxx,                     (numeric) The amount of the fee in " + CURRENCY_UNIT + ". This is negative and only available for the \n"
            "                                           'send' category of transactions.\n"
            "        \"abandoned\": xxx                  (bool) 'true' if the transaction has been abandoned (inputs are respendable). Only available for the \n"