Fix CMD to be in proper exec format (comma separated array surrounded by quotes)

docker/build/insights/Dockerfile

@@ -8,5 +8,5 @@ RUN /edx/app/edx_ansible/venvs/edx_ansible/bin/ansible-playbook insights.yml \
     -i '127.0.0.1,' -c local \
     -t "install:base,install:system-requirements,install:configuration,install:app-requirements,install:code" \
     -e@/ansible_overrides.yml
-CMD ["/edx/app/supervisor/venvs/supervisor/bin/supervisord -n --configuration /edx/app/supervisor/supervisord.conf"]
+CMD ["/edx/app/supervisor/venvs/supervisor/bin/supervisord", "-n", "--configuration", "/edx/app/supervisor/supervisord.conf"]
 EXPOSE 8110 18110