Issue #3064981: have a fallback clock type

Closes #3064981

modules/jst_clock/jst_clock.module

@@ -25,7 +25,10 @@ function jst_clock_jstwidget() {
   $ret->theme_function = 'jst_clock_show';
   $ret->js_name = 'Drupal.jstimer.jst_clock';
 
-  $clock_type = $config->get('jstimer_jst_clock_type');
+  $clock_type = 0;
+  if (!empty($config->get('jstimer_jst_clock_type'))) {
+    $clock_type = $config->get('jstimer_jst_clock_type');
+  }
 
   $ret->js_code = <<<JAVASCRIPT_CODE