Use an empty default if no github oauth keys
Use an empty default if no github oauth keys

seankelly/buildbot-infra,seankelly/buildbot-infra,buildbot/buildbot-infra,buildbot/buildbot-infra,seankelly/buildbot-infra,djmitche/buildbot-infra,djmitche/buildbot-infra,djmitche/buildbot-infra,buildbot/buildbot-infra