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.
assert(age >= 0);
                    if (age != 0)
                        age += 1;
                    dPriority += (double)nCredit * age;
                }
                const CAmount nChange = nValueIn - nValueToSelect;
                if (nChange > 0)
                {
                    
                    
                    
                    CScript scriptChange;
                    
                    if (coinControl && !boost::get<CNoDestination>(&coinControl->destChange))
                        scriptChange = GetScriptForDestination(coinControl->destChange);
                    
                    else
                    {
                        
                        
                        
                        
                        
                        
                        
                        CPubKey vchPubKey;
                        bool ret;
                        ret = reservekey.GetReservedKey(vchPubKey);
                        if (!ret)
                        {