increase the TLS handshake timeout
As of Firefox 58, the browser implements a TLS handshake timeout with a default value of 30 seconds. Previously, the timeout was a lot longer (maybe the same as the system TCP connect timeout, which is typically on the order of 10 minutes). We should decide whether we need a longer timeout for Tor-based browsing, e.g., 2 or 3 minutes. See: https://bugzilla.mozilla.org/show_bug.cgi?id=1393691