remove trailing comma

Change-Id: I3eefc93df3a09196b692afe0b4265012597038b3
Reviewed-on: https://gerrit.instructure.com/2513
Reviewed-by: JT Olds <jt@instructure.com>
Reviewed-by: Bracken Mosbacker <bracken@instructure.com>
Tested-by: Hudson <hudson@instructure.com>

public/javascripts/assignments.js

@@ -655,7 +655,7 @@
         $dialog.find("#assignment_group_delete").attr('checked', true);
         $dialog.dialog('close').dialog({
           autoOpen: false,
-          width: 500,
+          width: 500
         }).dialog('open').data('group_id', data.assignment_group_id);
         return;
       }