spec: properly skip kaltura sharding specs

specs_require_sharding will still run before blocks, so any expectations
in those blocks will fail when a sharding implementation is not present.

none of these tests rely on the expectation, so it's safe to just
convert it into a stub

Change-Id: Ib83fb3e50272a293b50f4df51c5183d4a93c2a82
Reviewed-on: https://gerrit.instructure.com/39608
Reviewed-by: Cody Cutrer <cody@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Paul Hinze <paulh@instructure.com>
QA-Review: Paul Hinze <paulh@instructure.com>