selectionChanged loop in 2.2.2

### Version of x-select: 2.2.2
### Ember Version / Ember CLI Version:

**Ember Version:** 2.6
**Ember CLI Version:** 2.6
### Expected Behavior

Initializing an `x-select` should not immediately trigger the changed `action`
### Actual Behavior

Initializing an `x-select` immediately triggers the changed `action`
### Info

We initialize an `x-select` component with the `value` set to a models attribute, `foo.bar`. Our `action` bubbles up and eventually triggers a `save` on the model, which worked absolutely fine until version `2.2.2` of this addon.

In `2.2.2` the `change` event is immediately triggered, which causes an infinite loop where the event causes a save, which then causes the property to change and the change event to fire again for some reason. We hide the select box while the model is saving (I think this is a fairly common pattern), which destroys the component. When the model finishes saving the component is re-created, which then again triggers the save event.

It is caused by this commit: ea9522537cd4a4eb0b6c46f283bb13f0f1989860