GF-57004: Re generate pages when childSize is updated.

When DataList is instanced, pages are generated with default childSize (100px).
After page1 is rendered with default value, we can know the actual childSize.
If actual childSize is not same with default value, that means initial page does not have proper controls in it.
So we should re generate pages.

Enyo-DCO-1.1-Signed-off-by: David Um david.um@lge.com