Edit wp-config.php to update WP by FTP-SSH2

WP FTP SSH wp-config.php

1. Install SSH2 and PHP mod, and restart Apache2
    |- #> sudo apt-get install libssh2-1-dev libssh2-php
    \- #> sudo service apache2 restart
2. Generate RSA keys, Create authorized_keys, and Update permissions
    |- #> ssh-keygen
    |- TIP: do not save them in your web directory
    |- #> cd .ssh/
    |- #> cp id_rsa.pub authorized_keys
    |- #> cd ../
    |- #> chmod 775 .ssh
    \- #> chmod 644 .ssh/*
3. Add FTP configuration lines in wp-config.php file

// START FTP EDIT
define( 'FTP_PUBKEY',	'/home/.ssh/id_rsa.pub');
define( 'FTP_PRIKEY',	'/home/.ssh/id_rsa');
define( 'FTP_USER', 	'ftp-user' );
define( 'FTP_PASS', 	'ftp-password' );
define( 'FTP_HOST', 	'ftp-host:22' );
define( 'FS_METHOD', 	'ssh2');
// END FTP EDIT