Undefined index: map_force_admin_ssl in .../domain-mapping/classes/class.do

Getting the error in the debug log

[23-Aug-2015 11:02:38 UTC] PHP Notice:  Undefined index: map_force_admin_ssl in /var/www/wp-content/plugins/domain-mapping/classes/class.domainmap.php on line 153
[23-Aug-2015 11:02:38 UTC] PHP Stack trace:
[23-Aug-2015 11:02:38 UTC] PHP   1. {main}() /var/www/wp-login.php:0
[23-Aug-2015 11:02:38 UTC] PHP   2. require() /var/www/wp-login.php:12
[23-Aug-2015 11:02:38 UTC] PHP   3. require_once() /var/www/wp-load.php:37
[23-Aug-2015 11:02:38 UTC] PHP   4. require_once() /var/www/wp-config.php:129
[23-Aug-2015 11:02:38 UTC] PHP   5. do_action() /var/www/wp-settings.php:353
[23-Aug-2015 11:02:38 UTC] PHP   6. call_user_func_array() /var/www/wp-includes/plugin.php:503
[23-Aug-2015 11:02:38 UTC] PHP   7. Domainmap_Module_Setup->register_scripts() /var/www/wp-includes/plugin.php:503
[23-Aug-2015 11:02:38 UTC] PHP   8. wp_register_script() /var/www/wp-content/plugins/domain-mapping/classes/Domainmap/Module/Setup.php:79
[23-Aug-2015 11:02:38 UTC] PHP   9. wp_scripts() /var/www/wp-includes/functions.wp-scripts.php:111
[23-Aug-2015 11:02:38 UTC] PHP  10. WP_Scripts->__construct() /var/www/wp-includes/functions.wp-scripts.php:23
[23-Aug-2015 11:02:38 UTC] PHP  11. WP_Scripts->init() /var/www/wp-includes/class.wp-scripts.php:34
[23-Aug-2015 11:02:38 UTC] PHP  12. do_action_ref_array() /var/www/wp-includes/class.wp-scripts.php:49
[23-Aug-2015 11:02:38 UTC] PHP  13. call_user_func_array() /var/www/wp-includes/plugin.php:579
[23-Aug-2015 11:02:38 UTC] PHP  14. wp_default_scripts() /var/www/wp-includes/plugin.php:579
[23-Aug-2015 11:02:38 UTC] PHP  15. admin_url() /var/www/wp-includes/script-loader.php:451
[23-Aug-2015 11:02:38 UTC] PHP  16. get_admin_url() /var/www/wp-includes/link-template.php:2837
[23-Aug-2015 11:02:38 UTC] PHP  17. apply_filters() /var/www/wp-includes/link-template.php:2867
[23-Aug-2015 11:02:38 UTC] PHP  18. call_user_func_array() /var/www/wp-includes/plugin.php:213
[23-Aug-2015 11:02:38 UTC] PHP  19. domain_map->domain_mapping_admin_url() /var/www/wp-includes/plugin.php:213