[tempest][gate] tempest-tox-plugin-sanity-check broken by whitebox-tempest-plugin

Hey all, A recent change in the whitebox-tempest-plugin [1] has broken the tempest-tox-plugin-sanity-check job (ex: [2]). The cause is a skipCheck that uses a whitebox-specific config option that had no default value and is obviously not set in any jobs outside of whitebox itself. When attempting to compare a None and an int, a TypeError is thrown. This has been fixed in [3]. The disruption should be minimal, but please don't: 1. recheck tempest until [3] merges 2. blacklist whitebox from the tempest-tox-plugin-sanity-check job :) Cheers! [1] https://review.opendev.org/#/c/699864/ [2] https://review.opendev.org/#/c/711049/8 [3] https://review.opendev.org/#/c/714539/