Quiz submit all and finish confirmation modal focuses on cancel

Issue
Form validation cues - The confirmation alertBox that pops up when the user submits his or her test has direct focus on the "Cancel" button instead of reading through the alert dialog first which makes it difficult for a screen reader user to understand the context.

Standard Level*
WCAG 2 3.3.1 (A) http://www.w3.org/WAI/WCAG20/quickref/#qr-minimize-error-identified

Impact
Serious

Example Link
http://next-qa/mod/quiz/summary.php?attempt=1305

Test Steps

1. Login as a student
2. navigate to course
3. Click on quiz
4. Click attempt quiz button
5. Click the next button until the end of the quiz
6. Click the submit all and Finnish button with screen reader on and hear no announcement that a popup has been opened.