DA - change warning dialog (quiz/discussion/calendar event)

fixes CNVS-16105

test plan:
 * setup DA
 * as a teacher
 * for each of the following
   - quiz
   - discussion
   - calendar event
 - create a new one with at least one section
   without an override
 > the warning dialog should match the new one for DA
   (http://f.cl.ly/items/2C0t2w0738220R2Z3N39/Image%202014-09-30%20at%205.00.32%20PM.png)
 - edit it and make sure there is at least one section
   without an override (same as before)
 > the warning dialog should be the new one as well

 * with DA off
   - the dialog should be the old version in all cases

Change-Id: I7b8ca6d35533d7a85f11e0cd1c2582d76dc39da7
Reviewed-on: https://gerrit.instructure.com/42368
Reviewed-by: Mike Nomitch <mnomitch@instructure.com>
QA-Review: Amber Taniuchi <amber@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Hilary Scharton <hilary@instructure.com>