Bug 1112135 - [Messages] When starting as an activity/notification/, delay threads rendering until the right panel is open. r=julien

About this ```meta```, maybe we just should use smth like  ```var transitionArgs = Object.assign({}, args);``` in [1] to not modify consumer's args?

[1] https://github.com/azasypkin/gaia/blob/d733b56f2bc857ed84a0411f3da0d6c5a70c0b73/apps/sms/js/navigation.js#L173