For some reason API sends us pusher auth keys without a proper pusher
key, ie. instead of "{actual_pusher_key}:{signature}" it sends
"key:{signature}". For now I'm just fixing it on the client, but this
needs further investigation in the API.
This was a combination of 2 bugs:
* we didn't do deep_merge on config in ruby app, so
that any nested properties set in the javascript app would be
overwritten
* channelPrefix was not properly set for Travis CI Pro
