[racket] Permission errors with nightlies?

> If you can tolerate errors provoked by bad snapshots, then I think
> building against the snapshot is a good choice. I doubt that the error
> rate has been as low as 1%, though

Maybe it's higher, but fortunately my perceived rate is that rate
multiplied the % of days Travis builds my projects, which is well
below 100%. :)


Anyway, the more I think about this it's really a limitation of Travis
CI. It would be great if I could exclude some of the build matrix
(e.g. nightlies) from contributing to stuff like the project's
pass/fail "badge" and notifications like "Broken!" emails.