Drop none cipher and MAC as they are not implemented

or not intended for production

Related: T85

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

doc/mainpage.dox

@@ -21,9 +21,9 @@ The libssh library provides:
 
  - <strong>Key Exchange Methods</strong>: <i>curve25519-sha256, curve25519-sha256@libssh.org, ecdh-sha2-nistp256, ecdh-sha2-nistp384, ecdh-sha2-nistp521</i>, diffie-hellman-group1-sha1, diffie-hellman-group14-sha1
  - <strong>Public Key Algorithms</strong>: ssh-ed25519, ecdsa-sha2-nistp256, ecdsa-sha2-nistp384, ecdsa-sha2-nistp521, ssh-rsa, rsa-sha2-512, rsa-sha2-256,ssh-dss
- - <strong>Ciphers</strong>: <i>aes256-ctr, aes192-ctr, aes128-ctr</i>, aes256-cbc (rijndael-cbc@lysator.liu.se), aes192-cbc, aes128-cbc, 3des-cbc, blowfish-cbc, none
+ - <strong>Ciphers</strong>: <i>aes256-ctr, aes192-ctr, aes128-ctr</i>, aes256-cbc (rijndael-cbc@lysator.liu.se), aes192-cbc, aes128-cbc, 3des-cbc, blowfish-cbc
  - <strong>Compression Schemes</strong>: zlib, <i>zlib@openssh.com</i>, none
- - <strong>MAC hashes</strong>: hmac-sha1, hmac-sha2-256, hmac-sha2-512, hmac-md5, none
+ - <strong>MAC hashes</strong>: hmac-sha1, hmac-sha2-256, hmac-sha2-512, hmac-md5
  - <strong>Authentication</strong>: none, password, public-key, keyboard-interactive, <i>gssapi-with-mic</i>
  - <strong>Channels</strong>: shell, exec (incl. SCP wrapper), direct-tcpip, subsystem, <i>auth-agent-req@openssh.com</i>
  - <strong>Global Requests</strong>: tcpip-forward, forwarded-tcpip