Example: https://courses.edx.org/courses/course-v1:HarvardX+GSD1x+1T2017/course/
Example: https://courses.edx.org/courses/course-v1:HarvardX+GSD1x+1T2017/course/

Pressing tab key until focus is on the Learn About Verified Certificates button. There is no visible focus indicator. This PR is to fix the issue.

appsembler/edx-platform,edx/edx-platform,jolyonb/edx-platform,eduNEXT/edunext-platform,EDUlib/edx-platform,arbrandes/edx-platform,eduNEXT/edx-platform,edx-solutions/edx-platform,stvstnfrd/edx-platform,eduNEXT/edunext-platform,cpennington/edx-platform,ESOedX/edx-platform,eduNEXT/edunext-platform,angelapper/edx-platform,stvstnfrd/edx-platform,angelapper/edx-platform,philanthropy-u/edx-platform,angelapper/edx-platform,msegado/edx-platform,stvstnfrd/edx-platform,appsembler/edx-platform,teltek/edx-platform,ESOedX/edx-platform,ahmedaljazzar/edx-platform,philanthropy-u/edx-platform,appsembler/edx-platform,EDUlib/edx-platform,eduNEXT/edunext-platform,mitocw/edx-platform,msegado/edx-platform,arbrandes/edx-platform,edx/edx-platform,appsembler/edx-platform,eduNEXT/edx-platform,ahmedaljazzar/edx-platform,edx/edx-platform,philanthropy-u/edx-platform,mitocw/edx-platform,jolyonb/edx-platform,ahmedaljazzar/edx-platform,teltek/edx-platform,edx/edx-platform,stvstnfrd/edx-platform,a-parhom/edx-platform,eduNEXT/edx-platform,eduNEXT/edx-platform,cpennington/edx-platform,a-parhom/edx-platform,philanthropy-u/edx-platform,angelapper/edx-platform,msegado/edx-platform,ESOedX/edx-platform,EDUlib/edx-platform,arbrandes/edx-platform,msegado/edx-platform,ESOedX/edx-platform,msegado/edx-platform,teltek/edx-platform,jolyonb/edx-platform,mitocw/edx-platform,jolyonb/edx-platform,teltek/edx-platform,ahmedaljazzar/edx-platform,cpennington/edx-platform,a-parhom/edx-platform,mitocw/edx-platform,a-parhom/edx-platform,arbrandes/edx-platform,cpennington/edx-platform,EDUlib/edx-platform,edx-solutions/edx-platform,edx-solutions/edx-platform,edx-solutions/edx-platform