Change FileCollectionStorage to not write 0 bytes to the next file at the end

Currently at the end of writing to a file it is likely that the offset+length will be equal to the next file offset. Usually while selecting files once we get to a file that is greater than our current offset+length we break out of the loop. I would consider the next file that has offset+length equal to the offset to be outside of the range that we should be writing to, so we should also break out for equals to.