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.
{
    CWalletDB walletdb(strWalletFile);
    CAccount account;
    walletdb.ReadAccount(strAccount, account);
    if (!bForceNew) {
        if (!account.vchPubKey.IsValid())
            bForceNew = true;
        else {
            
            CScript scriptPubKey = GetScriptForDestination(account.vchPubKey.GetID());
            for (map<uint256, CWalletTx>::iterator it = mapWallet.begin();
                 it != mapWallet.end() && account.vchPubKey.IsValid();
                 ++it)
                BOOST_FOREACH(const CTxOut& txout, (*it).second.tx->vout)
                    if (txout.scriptPubKey == scriptPubKey) {
                        bForceNew = true;
                        break;
                    }
        }
    }
    
    if (bForceNew) {
        if (!GetKeyFromPool(account.vchPubKey))
            return false;