obfsproxy makes tor warn when one bridge is down
When you run the fancy new flashproxy/obfsproxy bundle: https://blog.torproject.org/blog/combined-flash-proxy-pyobfsproxy-browser-bundles you get
Jan 19 15:09:17.120 [Warning] Proxy Client: unable to connect to 18.104.22.168:55564 ("server rejected connection")
That's because that bridge is down currently.
When a bridge fails, we should probably only [warn] if no bridges have succeeded.