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.
{
    return std::max(minTxFee.GetFee(nTxBytes), ::minRelayTxFee.GetFee(nTxBytes));
}
CAmount CWallet::GetMinimumFee(unsigned int nTxBytes, unsigned int nConfirmTarget, const CTxMemPool& pool)
{
    
    CAmount nFeeNeeded = payTxFee.GetFee(nTxBytes);
    
    if (nFeeNeeded == 0) {
        int estimateFoundTarget = nConfirmTarget;
        nFeeNeeded = pool.estimateSmartFee(nConfirmTarget, &estimateFoundTarget).GetFee(nTxBytes);
        
        if (nFeeNeeded == 0)
            nFeeNeeded = fallbackFee.GetFee(nTxBytes);
    }
    
    nFeeNeeded = std::max(nFeeNeeded, GetRequiredFee(nTxBytes));
    
    if (nFeeNeeded > maxTxFee)
        nFeeNeeded = maxTxFee;
    return nFeeNeeded;
}
DBErrors CWallet::LoadWallet(bool& fFirstRunRet)