Fix class on dashboard's verify now button

lms/templates/dashboard/_dashboard_course_listing.html

@@ -308,7 +308,7 @@ from student.helpers import (
               % endif
             </div>
             <div class="verification-cta">
-              <a href="${reverse('verify_student_verify_now', kwargs={'course_id': unicode(course_overview.id)})}" class="cta" data-course-id="${course_overview.id}">${_('Verify Now')}</a>
+              <a href="${reverse('verify_student_verify_now', kwargs={'course_id': unicode(course_overview.id)})}" class="btn" data-course-id="${course_overview.id}">${_('Verify Now')}</a>
             </div>
           % elif verification_status['status'] == VERIFY_STATUS_SUBMITTED:
             <h4 class="message-title">${_('You have already verified your ID!')}</h4>