If server requires TLS and clients are connecting, and a Connz
request is made while clients are still in TLS Handshake, the
call to tls.Conn.ConnectionState() would block for the duration
of the handshake. This would cause the overall http request to
take too long.
We will now not try to gather TLSVersion and TLSCipher from a
client that is still in TLS handshake.
Resolves#600