Backed out changesets 5cd05df56f67, 6344d6606517, and 098a43b537e9 (bug 980027).
Bug 984873 - Hide banner for the rest of the session after the user has clicked on it. r=bnicholson, a=sledru
Bug 985184 - Package WebappsUpdaterTimer.js with Fennec. r=mfinkle, a=sledru
Bug 985195 - Give WebappsUpdateTimer a unique ID. r=mfinkle, a=sledru