I don't understand that. If you remove the ethernet shield and connect the LCD shield directly to the Arduino with the LCD shield pins still bent and the jumper, does the LCD work?
add: If that doesn't work, remove the jumper and bend pin 4 back to connect to the Arduino. Check the LCD again. And change this back to pin 4
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);