Apple’s flagship store in Beijing was forced to close its doors early today after a group of iPhone 4 scalpers created a chaotic scene. MIC Gadget reports that Apple removed its limitation on the number of contract-free iPhone 4 units any single customer could buy at the store, perhaps unintentionally paving the way for the problems ahead. The store opened at 7:00 a.m. local time, but closed only three hours later, with many customers left in…