[entities] fix bug introduce when porting to 3.9

entities.py

@@ -23,8 +23,8 @@
         rql = ('Any E ORDERBY D DESC '
                'WHERE E is BlogEntry, E entry_of X, X eid %s, E creation_date D'
                )
-        return self._cw.build_url(rql=rql % self.eid, vid='rss',
-                              vtitle=self.dc_title())
+        return self._cw.build_url(rql=rql % self.entity.eid, vid='rss',
+                                  vtitle=self.entity.dc_title())
 
 class BlogISiocContainerAdapter(EntityAdapter):
     __regid__ = 'ISiocContainer'
@@ -34,7 +34,7 @@
         return 'Weblog'
 
     def isioc_items(self):
-        return self.reverse_entry_of
+        return self.entity.reverse_entry_of
 
 
 class BlogEntry(AnyEntity):