Bug 1068109 - Restore 2s delay before callscreen is closed.

Actually, this isn't necessary at all. This test could be written as:
```js
this.sinon.spy(MockBluetoothHelperInstance, 'connectSco');
MockNavigatorMozTelephony.active = null;
CallsHandler.switchToDefaultOut(false);
sinon.assert.notCalled(MockBluetoothHelperInstance.connectSco);
```