Opt-out from TLS-specific settings
We should have an opt-out from the following TLS settings:
"security.ssl.require_safe_negotiation" "security.ssl.treat_unsafe_negotiation_as_broken"
Even though this is not such a good idea, but many servers do not support TLS with secure renegotiation (or are using an older version of the protocol), and because we are enforcing this setting, some users are not able to use TorBirdy at all.