[SSL Observatory] localhost Tor detection breaks once the user has picked "submit certs without Tor"
The way that submitting certs directly is implemented in the observatory is by setting use_custom_proxy to True and configuring the proxy to be a passthrough.
But that state confuses the code that tries to tell whether Tor is available for routing Observatory requests:
https://gitweb.torproject.org/https-everywhere.git/blob/HEAD:/src/components/ssl-observatory.js#l734
What that means is if the user picks "submit certs even if Tor is not available", then next time they restart Firefox, "submit through Tor" will no longer be an option though Tor is running on localhost:9050.
I think this blocks 3.0 stable.