Travis.ci OAuth hack

[hugomg]

I got an e-mail from Github saying that hackers were using Travis OAuth tokens to access organization data, or something like that. I don't believe this is a problem for us because we had no private data to hide, but it did bring to my attention that Travis was still linked to our organization's account. We switched to Github CI a while back, but had not revoked Travis' access permissions. Well, I have done that now.