fix none value establishment description

apps/establishment/management/commands/add_establishment_description.py

@@ -31,8 +31,10 @@ class Command(BaseCommand):
                 if new_date > date:
                     valid_reviews[r_id] = (establishment_id, new_date)
 
-        text_qs = ReviewTexts.objects.filter(
-            review_id__in=(r_id for r_id in valid_reviews.keys())
+        text_qs = ReviewTexts.objects.exclude(
+            locale__isnull=True
+        ).filter(
+            review_id__in=(r_id for r_id in valid_reviews.keys()),
         ).values_list(
             'review__establishment_id',
             'locale',