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.
{
        nWalletVersion = FEATURE_BASE;
        nWalletMaxVersion = FEATURE_BASE;
        fFileBacked = false;
        nMasterKeyMaxID = 0;
        pwalletdbEncryption = NULL;
        nOrderPosNext = 0;
        nNextResend = 0;
        nLastResend = 0;
        nTimeFirstKey = 0;
        fBroadcastTransactions = false;
    }
    std::map<uint256, CWalletTx> mapWallet;
    std::list<CAccountingEntry> laccentries;
    typedef std::pair<CWalletTx*, CAccountingEntry*> TxPair;
    typedef std::multimap<int64_t, TxPair > TxItems;
    TxItems wtxOrdered;
    int64_t nOrderPosNext;
    std::map<uint256, int> mapRequestCount;
    std::map<CTxDestination, CAddressBookData> mapAddressBook;
    CPubKey vchDefaultKey;
    std::set<COutPoint> setLockedCoins;
    int64_t nTimeFirstKey;
    const CWalletTx* GetWalletTx(const uint256& hash) const;
    
    bool CanSupportFeature(enum WalletFeature wf) { AssertLockHeld(cs_wallet); return nWalletMaxVersion >= wf; }