Remove unused .cascading from unit test for __table_cls__ feature

Two independent gerrits for 04bbad660b
and ec1700ba29 produce a failure
when merged due to new warning.
will merge into rel_1_1 as well for completeness even though
warning is not there.

Change-Id: I1bd494d205107d8b2a30d475a22c61a59b70985b

test/ext/declarative/test_basic.py

@@ -1159,7 +1159,7 @@ class DeclarativeTest(DeclarativeTestBase):
         from sqlalchemy.schema import Column, PrimaryKeyConstraint
 
         class AutoTable(object):
-            @declared_attr.cascading
+            @declared_attr
             def __tablename__(cls):
                 return cls.__name__