Fix inconsistent use of blacklist and excludelist.

[grembo]

Summary

Obvious. I still think this should be done in a backwards compatible way
and that "excludelist" (without any spacing, camel-, or snake-casing) isn't
proper English. But what do I know, I'm just a stupid foreigner.

[grembo]

The change this was based on was backed out in rS363060 to come up with a better strategy. This renders this change pointless, as I assume the next attempt will include this anyway.