make owncloud multi-virtualhost

apache_vhost.conf

DocumentRoot /var/www/owncloud
<Directory /var/www/owncloud/>
  AllowOverride All
  <FilesMatch ".+\.ph(p[345]?|t|tml)$">
      SetHandler application/x-httpd-php
  </FilesMatch>
</Directory>

<Directory /var/www/owncloud.domain.net/htdocs/owncloud>
  Order allow,deny
  Deny from all
</Directory>

SetEnv OC_DOMAIN owncloud.domain.net
SetEnv OC_DBNAME dbname
SetEnv OC_DBUSER dbuser
SetEnv OC_DBPASS dbpass

config.php

// /var/www/owncloud/lib/private/config.php

private function writeData() {
  // (coment all function
}

oc_config.php

// /var/www/owncloud/config/config.php

// original idea from http://owncloud.10557.n7.nabble.com/Multiple-Instances-on-one-server-td7644.html
$DOMAIN = getenv('OC_DOMAIN');
$DBNAME = getenv('OC_DBNAME');
$DBUSER = getenv('OC_DBUSER');
$DBPASS = getenv('OC_DBPASS');
$DBHOST = 'localhost';

$INSTANCE = substr(md5($DOMAIN),0,13); //Generate instance id for every domain

$CONFIGURED = strlen($DOMAIN) > 0 &&
    strlen($DBNAME) > 0 &&
    strlen($DBUSER) > 0 &&
    strlen($DBPASS) > 0;

if ( ! $CONFIGURED ) {
    echo 'Server not configured for '.$_SERVER['HTTP_HOST'];
    throw new Exception('Not configured for '.$_SERVER['HTTP_HOST']);
}

//Check if already exists the instance or not
$INSTALLED = false;
$con = mysqli_connect($DBHOST, $DBUSER, $DBPASS, $DBNAME);
if ( !mysqli_connect_errno() ) { // Check connection
    $result = mysqli_query($con,"SELECT * FROM oc_users");
    $INSTALLED = mysqli_num_rows($result) > 0;
}
mysqli_close($con);

$CONFIG = array (
    'instanceid'    => $INSTANCE,
    'passwordsalt'  => 'your_salt_here',
    'datadirectory' => '/var/www/'.$DOMAIN.'/htdocs/owncloud',
    'dbtype'        => 'mysql',
    'dbtableprefix' => 'oc_',
    'dbhost'        => $DBHOST,
    'dbname'        => $DBNAME,
    'dbuser'        => $DBUSER,
    'dbpassword'    => $DBPASS,
    'version'       => '6.0.0.14',
    'installed'     => $INSTALLED,
    'maintenance'   => false,
    'theme'         => '',
    'loglevel'      => '2',
    'trashbin_retention_obligation' => 10,
);

setup.php

// /var/www/owncloud/lib/private/setup.php

//generate a random salt that is used to salt the local user passwords
//$salt = OC_Util::generateRandomBytes(30);
//OC_Config::setValue('passwordsalt', $salt);

// read salt from config file
$salt = OC_Config::getValue('passwordsalt');