If one calls `fundrawtransaction`, the change address will be retrieved from the keypool, though, this key/address will always be returned to the pool, leading to the problem that the next `getnewaddress()` call will restult in the same key/address.

Either we remove the auto-change-address (users would need to call `getrawchangeaddress` first [current best practice anyway]) or we add a call to keep/mark a specific key/address as change (after one have sent the funded raw transaction).

Reported by @NicolasDorier on IRC.
if (request.fHelp || request.params.size() > 0)
        throw runtime_error(
            "listlockunspent\n"
            "\nReturns list of temporarily unspendable outputs.\n"
            "See the lockunspent call to lock and unlock transactions for spending.\n"
            "\nResult:\n"
            "[\n"
            "  {\n"
            "    \"txid\" : \"transactionid\",     (string) The transaction id locked\n"
            "    \"vout\" : n                      (numeric) The vout value\n"
            "  }\n"
            "  ,...\n"
            "]\n"
            "\nExamples:\n"
            "\nList the unspent transactions\n"
            + HelpExampleCli("listunspent", "") +
            "\nLock an unspent transaction\n"
            + HelpExampleCli("lockunspent", "false \"[{\\\"txid\\\":\\\"a08e6907dbbd3d809776dbfc5d82e371b764ed838b5655e72f463568df1aadf0\\\",\\\"vout\\\":1}]\"") +
            "\nList the locked transactions\n"
            + HelpExampleCli("listlockunspent", "") +
            "\nUnlock the transaction again\n"
            + HelpExampleCli("lockunspent", "true \"[{\\\"txid\\\":\\\"a08e6907dbbd3d809776dbfc5d82e371b764ed838b5655e72f463568df1aadf0\\\",\\\"vout\\\":1}]\"") +
            "\nAs a json rpc call\n"
            + HelpExampleRpc("listlockunspent", "")
        );
    LOCK2(cs_main, pwalletMain->cs_wallet);
    vector<COutPoint> vOutpts;
    pwalletMain->ListLockedCoins(vOutpts);
    UniValue ret(UniValue::VARR);
    BOOST_FOREACH(COutPoint &outpt, vOutpts) {