No 5.x branches listed on https://packagist.org/packages/drush/drush...
@ -19,7 +19,7 @@ pear channel-discover pear.phpqatools.org
pear channel-discover pear.netpirates.net
pear install pear/PHP_CodeSniffer-1.4.8
pear install pear.phpunit.de/phpcpd
composer global require drush/drush:5.9.0
composer global require drush/drush:6.x
phpenv rehash
drush dl --yes drupal
cd drupal-*