Cannot access list of questionnaires if there is a template questionnaire

Courses with instances of the questionnaire activity, if there is an instance that has a "realm" of "template" will cause the page mod/questionnaire/index.php to throw a coding_error.

Test:

1. Add a questionnaire activity.
2. Create and view activity.
3. Click "Advanced settings" tab.
4. Set "Questionnaire Type" = "Template"
5. Save settings
6. Go to course site/sections view
7. Click "Quesitonnaires" in the course menu block.