spec: replace it_should_behave_like with include_examples

Change-Id: I8a10679218b9a6ff8485b7822a21c704bdfaa398
Reviewed-on: https://gerrit.instructure.com/29213
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>