If you are looking for security lab, redirecting to the main website will not help the user at all. We can just check if we don't have any references to security or other labs/spins which are not available for F29. That will prevent Google from crawling something that doesn't exist.

I am closign this as a won't fix, as we cannot do much here. We already give Google a 404, which should be enough. Sure we ''could'' tell Google that page doesn't exist and we want to hide it from search results, but this can take a long time. Maybe when Google is ready we are in the middle of the F30 release cycle (Beta or GA), and at that point it could also be that we want it to be listed again ;)
So, let's keep it as it is and hope Google understands the webpage has gone for now.