Merge pull request #9693 from lightsofapollo/notify-on-sync-error

Bug 870664 - Send notification when account fails to sync r=kgrandon (tests/lint pass locally)
Conflicts:

	apps/calendar/js/store/account.js
	apps/calendar/locales/calendar.en-US.properties
	apps/calendar/test/unit/controllers/alarm_test.js