emberjs/ember.js — pull request #5586 by yonjah (2014-09-14 10:20:59+00:00)
Title: ES6 circulare dependencies in ember-metal properties and property_set

For the deprecateProperty method we need to have access to the set and get method
but the property_set method also relies on the defineProperty method which is in the same file
I think the good and easy way to solve it is to move deprecateProperty so thats what this fix does.