When a pass of CreateTransaction fails to select enough bitcoin to meet the nFeeNeeded the next pass through may select a far smaller collection of inputs.  Currently it will continue to use the old fee amount based on the larger set of inputs, which can cause a non-trivial over-payment.

This may be the cause of the behavior reported here: https://www.reddit.com/r/Bitcoin/comments/5ltw5n/bitcoin_core_v0131_sends_enormously_high_fee/

Long ago fixing this was tricky due to a catch-22 between signing the transaction and knowing how much fee was required.  But after #9465 the whole algorithm will run using a dummy signature, so when there is already a change output fixing up the fee after finding a sufficient transaction should be a matter of a ~2 line change.

{
    if (nIndex != -1)
        pwallet->ReturnKey(nIndex);
    nIndex = -1;
    vchPubKey = CPubKey();
}
void CWallet::GetAllReserveKeys(set<CKeyID>& setAddress) const
{
    setAddress.clear();
    CWalletDB walletdb(strWalletFile);
    LOCK2(cs_main, cs_wallet);
    BOOST_FOREACH(const int64_t& id, setKeyPool)
    {
        CKeyPool keypool;
        if (!walletdb.ReadPool(id, keypool))
            throw runtime_error(std::string(__func__) + ": read failed");
        assert(keypool.vchPubKey.IsValid());
        CKeyID keyID = keypool.vchPubKey.GetID();
        if (!HaveKey(keyID))
            throw runtime_error(std::string(__func__) + ": unknown key in key pool");
        setAddress.insert(keyID);
    }
}
void CWallet::UpdatedTransaction(const uint256 &hashTx)