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 (!EnsureWalletIsAvailable(request.fHelp))
        return NullUniValue;
    if (request.fHelp || request.params.size() != 1)
        throw runtime_error(
            "abandontransaction \"txid\"\n"
            "\nMark in-wallet transaction <txid> as abandoned\n"
            "This will mark this transaction and all its in-wallet descendants as abandoned which will allow\n"
            "for their inputs to be respent.  It can be used to replace \"stuck\" or evicted transactions.\n"
            "It only works on transactions which are not included in a block and are not currently in the mempool.\n"
            "It has no effect on transactions which are already conflicted or abandoned.\n"
            "\nArguments:\n"
            "1. \"txid\"    (string, required) The transaction id\n"
            "\nResult:\n"
            "\nExamples:\n"
            + HelpExampleCli("abandontransaction", "\"1075db55d416d3ca199f55b6084e2115b9345e16c5cf302fc80e9d5fbf5d48d\"")
            + HelpExampleRpc("abandontransaction", "\"1075db55d416d3ca199f55b6084e2115b9345e16c5cf302fc80e9d5fbf5d48d\"")
        );
    LOCK2(cs_main, pwalletMain->cs_wallet);
    uint256 hash;
    hash.SetHex(request.params[0].get_str());
    if (!pwalletMain->mapWallet.count(hash))
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid or non-wallet transaction id");
    if (!pwalletMain->AbandonTransaction(hash))
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Transaction not eligible for abandonment");
    return NullUniValue;
}
UniValue backupwallet(const JSONRPCRequest& request)