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.
{
    
    if (IsCoinBase() && GetBlocksToMaturity() > 0)
        return 0;
    CAmount credit = 0;
    if (filter & ISMINE_SPENDABLE)
    {
        
        if (fCreditCached)
            credit += nCreditCached;
        else
        {
            nCreditCached = pwallet->GetCredit(*this, ISMINE_SPENDABLE);