Refresh promo notifications as they're fetched

The "guard" existed for notification scheduling was preventing
"turn-off a promo" and "update a promo" scenarios.
Yet I do not believe it was adding any actual safety: if things
on a server backend go wrong, the clients will be affected one
way or the other, and it is better to have an option to shut
the malformed promo down "as quickly as possible" (~in 12-24 hours).

BUG=
TEST=


Review URL: https://chromiumcodereview.appspot.com/10696204

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@146462 0039d316-1c4b-4281-b951-d872f2087c98