[celery#305] ChordCounter moved from abstract module to generic module.

Added some minor changes.

---

Resolves celery#305

Fixes celery#314

Author: jose-padin

django_celery_results/models/abstract.py

@@ -182,9 +182,9 @@ class Meta:
         """Table information."""
 
         abstract = True
-        ordering = ['-date_done']
         verbose_name = _('group result')
         verbose_name_plural = _('group results')
+        ordering = ['-date_done']
 
         # Explicit names to solve https://code.djangoproject.com/ticket/33483
         indexes = [