Add more missing app_labels

I don't know how I missed them. I think I must've made a mistake while
heavily rebasing this branch; it's the second time I'm surprised to not
find certain changes I'm confident I did.

oscar/apps/address/abstract_models.py

 
     class Meta:
         abstract = True
+        app_label = 'address'
         verbose_name = _('Country')
         verbose_name_plural = _('Countries')
         ordering = ('-display_order', 'printable_name',)
 
     class Meta:
         abstract = True
+        # ShippingAddress is registered in order/models.py
+        app_label = 'order'
         verbose_name = _("Shipping address")
         verbose_name_plural = _("Shipping addresses")
 
 
     class Meta:
         abstract = True
+        app_label = 'address'
         verbose_name = _("User address")
         verbose_name_plural = _("User addresses")
         ordering = ['-num_orders']
 
     class Meta:
         abstract = True
+        # BillingAddress is registered in order/models.py
+        app_label = 'order'
         verbose_name = _("Billing address")
         verbose_name_plural = _("Billing addresses")
 

oscar/apps/analytics/abstract_models.py

 
     class Meta:
         abstract = True
+        app_label = 'analytics'
         ordering = ['-num_purchases']
         verbose_name = _('Product record')
         verbose_name_plural = _('Product records')
 
     class Meta:
         abstract = True
+        app_label = 'analytics'
         verbose_name = _('User record')
         verbose_name_plural = _('User records')
 
 
     class Meta:
         abstract = True
+        app_label = 'analytics'
         verbose_name = _('User product view')
         verbose_name_plural = _('User product views')
 
 
     class Meta:
         abstract = True
+        app_label = 'analytics'
         verbose_name = _("User search query")
         verbose_name_plural = _("User search queries")
 

oscar/apps/promotions/models.py

 
     class Meta:
         abstract = True
+        app_label = 'promotions'
         ordering = ['-clicks']
         verbose_name = _("Linked Promotion")
         verbose_name_plural = _("Linked Promotions")
         return reverse('promotions:page-click',
                        kwargs={'page_promotion_id': self.id})
 
-    class Meta:
+    class Meta(LinkedPromotion.Meta):
         verbose_name = _("Page Promotion")
         verbose_name_plural = _("Page Promotions")
 
         return reverse('promotions:keyword-click',
                        kwargs={'keyword_promotion_id': self.id})
 
-    class Meta:
+    class Meta(LinkedPromotion.Meta):
         verbose_name = _("Keyword Promotion")
         verbose_name_plural = _("Keyword Promotions")