fix rails2_compatibility_spec for rails 3

still runs :after hooks even though it's pending

Change-Id: Ibb0909084a5f6cc279049d216485db779006b210
Reviewed-on: https://gerrit.instructure.com/30394
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>
QA-Review: James Williams  <jamesw@instructure.com>