Pass the original index in the array into the function

I recently came into a situation where I needed to use the original array index in `_.remove`

Current functionality was passing in the current index in the modified array
So if you were removing every value in the array, index would always be 0

I have made the change to pass the original index instead of the currentIndex as I couldn't figure out what anyone would get out of using the currentIndex, most of the time you will just use the value instead of this[index]...but I might be missing something