ssl_sock_init() does nothing, so remove it...
TLS is pretty boring without TLS extensions... unifdef OPENSSL_NO_TLSEXT,
which was already done for libssl some time back.
Document the -servername option for openssl(1) s_client.

Based on a diff from Rusty (rustyl at outband dot net) and OpenSSL.
missing outlen in tls_write decl
More OPENSSL_NO_TLSEXT clean up.