Fix backwards migration not running after refactor

Author: jleclanche

postgres_composite_types/operations.py

@@ -47,4 +47,6 @@ def database_forwards(self, app_label, schema_editor, from_state, to_state):
         )
 
     def database_backwards(self, app_label, schema_editor, from_state, to_state):
-        return sql_drop_type(self.Meta.db_type, schema_editor=schema_editor)
+        schema_editor.execute(
+            sql_drop_type(self.Meta.db_type, schema_editor=schema_editor)
+        )

tests/test_field.py

@@ -84,6 +84,7 @@ def test_migration(self):
 
         # Run the migration forwards to create the type again
         migrate(self.migrate_to)
+        self.assertTrue(does_type_exist(SimpleType._meta.db_type))
 
         # The signal should have been sent
         self.assertEqual(signal_func.call_count, 1)