Bug 1059106 - [settings] move root panel airplane mode item into panels r=arthurcc

...root
This locator is wrong.
`//input[@class='airplaneMode-input']/..` = Parent of a input element that has the `class` attribute `equal` to `airplaneMode-input`

This doesn't apply to the code  because the `input` element has the  `class` attribute `equal` to `airplaneMode-input uninit`  
```html
<label class="pack-switch">
    <input class="airplaneMode-input uninit" type="checkbox"/>
    <span id="menuItem-airplaneMode" class="menu-item" data-icon="airplane" data-l10n-id="airplaneMode"/>
</label>
```

We can use:
`//input[contains(@class, 'airplaneMode-input')]/..` or `//input[@class='airplaneMode-input uninit']/..`