LN: Some fixes & cleanup

- Fix bug that the notification is launched when a button on it is pressed
- Show new notifications first

Change-Id: I87db92a7ee4eb9329ec1ec69008e612a619d5c91
LN: Fix FC on launching hangouts notification

Change-Id: Idf411bd2b4995f0b53767e99597efd98ce0596b3