Removed unneeded __init__() in PostgreSQL DatabaseWrapper.

django/db/backends/postgresql/base.py

@@ -139,10 +139,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
     features_class = DatabaseFeatures
     introspection_class = DatabaseIntrospection
     ops_class = DatabaseOperations
-
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
-        self._named_cursor_idx = 0
+    # PostgreSQL backend-specific attributes.
+    _named_cursor_idx = 0
 
     def get_connection_params(self):
         settings_dict = self.settings_dict