martian: detect and better handle direct TLS access

[mmatczuk]

If you try to send TLS handshake to HTTP proxy we get

[error] failed to read request: malformed HTTP request "\x16\x03\x01\x00\xc5\x01\x00\....

We could improve the logging in this case by reading the TLS handshake (with SNI) and printing more actionable error message.