change override handling with no sections

closes OUT-2191

Test plan:
- create a course with no sections
- enable mastery paths in the course
- create a quiz assigned to "Mastery Paths" only
- verify that quiz is saved assigned
  to Mastery Paths only, not Everyone Else as well
- create a discussion topic assigned to
  "Mastery Paths" only
- verify that discussion is saved assigned
  to Mastery Paths only, not Everyone Else as well

Change-Id: I3af0c58f54a6f9a7ee612ab87276984574ef08d0
Reviewed-on: https://gerrit.instructure.com/155222
Reviewed-by: Augusto Callejas <acallejas@instructure.com>
Reviewed-by: Neil Gupta <ngupta@instructure.com>
Tested-by: Jenkins
QA-Review: Dariusz Dzien <ddzien@instructure.com>
Product-Review: Sidharth Oberoi <soberoi@instructure.com>

app/coffeescripts/views/DiscussionTopics/EditView.coffee

@@ -377,7 +377,7 @@ define [
       data.unlock_at = defaultDate?.get('unlock_at') or null
       data.due_at = defaultDate?.get('due_at') or null
       data.assignment_overrides = @dueDateOverrideView.getOverrides()
-      data.only_visible_to_overrides = @dueDateOverrideView.containsSectionsWithoutOverrides()
+      data.only_visible_to_overrides = !@dueDateOverrideView.overridesContainDefault()
 
       assignment = @model.get('assignment')
       assignment or= @model.createAssignment()

public/javascripts/quizzes.js

@@ -1848,7 +1848,7 @@ const lockedItems = lockManager.isChildContent() ? lockManager.getItemLocks() :
         data.allowed_attempts = attempts;
         data['quiz[allowed_attempts]'] = attempts;
         var overrides = overrideView.getOverrides();
-        data['quiz[only_visible_to_overrides]'] = overrideView.containsSectionsWithoutOverrides();
+        data['quiz[only_visible_to_overrides]'] = !overrideView.overridesContainDefault()
         if (overrideView.containsSectionsWithoutOverrides() && !hasCheckedOverrides) {
           var sections = overrideView.sectionsWithoutOverrides();
           var missingDateView = new MissingDateDialog({
@@ -4293,4 +4293,3 @@ const lockedItems = lockManager.isChildContent() ? lockManager.getItemLocks() :
       }
     }).triggerHandler('change');
   });
-