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.

#include "wallet/wallet.h"
#include "base58.h"
#include "checkpoints.h"
#include "chain.h"
#include "wallet/coincontrol.h"
#include "consensus/consensus.h"
#include "consensus/validation.h"
#include "key.h"
#include "keystore.h"
#include "validation.h"
#include "net.h"
#include "policy/policy.h"
#include "primitives/block.h"
#include "primitives/transaction.h"
#include "script/script.h"
#include "script/sign.h"
#include "timedata.h"
#include "txmempool.h"
#include "util.h"
#include "ui_interface.h"
#include "utilmoneystr.h"
#include <assert.h>
#include <boost/algorithm/string/replace.hpp>