BHV-8206: Call the super of the constructor.

Issue
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If there are child components of `enyo.ModelController`, an exception is thrown at create time: http://jsfiddle.net/aarontam/pg6Dr/

Fix
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Call the super of `constructor` at create time.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>