contentInset，adjustContentCellsCenter一起设置时必现不能居中的bug

[HungryFour]

   self.title = @"TabPagerControllerDemoController";
    self.tabBarHeight = 50;
    self.tabBar.contentInset = UIEdgeInsetsMake(0, 50, 0, 50);
    self.tabBar.layout.barStyle = TYPagerBarStyleProgressView;
//    self.tabBar.layout.cellWidth = CGRectGetWidth(self.view.frame)/3;
    self.tabBar.layout.cellSpacing = 0;
    self.tabBar.layout.cellEdging = 0;
    self.tabBar.layout.adjustContentCellsCenter = YES;
    self.dataSource = self;
    self.delegate = self;

设置self.tabBar.contentInset 后再设置self.tabBar.layout.adjustContentCellsCenter。出现不能居中的bug