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.
strFailReason = _("Keypool ran out, please call keypoolrefill first");
                            return false;
                        }
                        scriptChange = GetScriptForDestination(vchPubKey.GetID());
                    }
                    CTxOut newTxOut(nChange, scriptChange);
                    
                    
                    
                    if (nSubtractFeeFromAmount > 0 && newTxOut.IsDust(dustRelayFee))
                    {
                        CAmount nDust = newTxOut.GetDustThreshold(dustRelayFee) - newTxOut.nValue;
                        newTxOut.nValue += nDust; 
                        for (unsigned int i = 0; i < vecSend.size(); i++) 
                        {
                            if (vecSend[i].fSubtractFeeFromAmount)
                            {
                                txNew.vout[i].nValue -= nDust;
                                if (txNew.vout[i].IsDust(dustRelayFee))
                                {
                                    strFailReason = _("The transaction amount is too small to send after the fee has been deducted");
                                    return false;
                                }
                                break;
                            }
                        }
                    }
                    
                    
                    if (newTxOut.IsDust(dustRelayFee))