[TIMOB-19908] iOS: Ti.UI.ScrollableView was not shown

<ios>
  <use-autolayout>true</use-autolayout>
</ios>

var win = Ti.UI.createWindow(),
  view0 = Ti.UI.createView({
    backgroundColor: 'red'
  }),
  view1 = Ti.UI.createView({
    backgroundColor: 'green'
  }),
  view2 = Ti.UI.createView({
    backgroundColor: 'blue'
  }),
  scrollableview = Ti.UI.createScrollableView({
    width: 200, // not the Ti.UI.FILL or SIZE
    height: 200, // not the Ti.UI.FILL or SIZE
    views: [
      view0,
      view1,
      view2
    ]
  });

win.add(scrollableview);
win.open();