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.
+ HelpExampleCli("sendfrom", "\"tabby\" \"1M72Sfpbz1BPpXFHz9m3CdqATR44Jvaydd\" 0.01 6 \"donation\" \"seans outpost\"") +
            "\nAs a json rpc call\n"
            + HelpExampleRpc("sendfrom", "\"tabby\", \"1M72Sfpbz1BPpXFHz9m3CdqATR44Jvaydd\", 0.01, 6, \"donation\", \"seans outpost\"")
        );
    LOCK2(cs_main, pwalletMain->cs_wallet);
    string strAccount = AccountFromValue(request.params[0]);
    CBitcoinAddress address(request.params[1].get_str());
    if (!address.IsValid())
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid Bitcoin address");
    CAmount nAmount = AmountFromValue(request.params[2]);
    if (nAmount <= 0)
        throw JSONRPCError(RPC_TYPE_ERROR, "Invalid amount for send");
    int nMinDepth = 1;
    if (request.params.size() > 3)
        nMinDepth = request.params[3].get_int();
    CWalletTx wtx;
    wtx.strFromAccount = strAccount;
    if (request.params.size() > 4 && !request.params[4].isNull() && !request.params[4].get_str().empty())
        wtx.mapValue["comment"] = request.params[4].get_str();
    if (request.params.size() > 5 && !request.params[5].isNull() && !request.params[5].get_str().empty())
        wtx.mapValue["to"]      = request.params[5].get_str();
    EnsureWalletIsUnlocked();
    
    CAmount nBalance = pwalletMain->GetAccountBalance(strAccount, nMinDepth, ISMINE_SPENDABLE);
    if (nAmount > nBalance)
        throw JSONRPCError(RPC_WALLET_INSUFFICIENT_FUNDS, "Account has insufficient funds");
    SendMoney(address.Get(), nAmount, false, wtx);
    return wtx.GetHash().GetHex();
}
UniValue sendmany(const JSONRPCRequest& request)