Make is called incorrectly

When setting the working-copy option on the hostmaster install process, the options are passed through incorrectly.

This results in calling something like:

ackend invoke: php /var/aegir/drush/drush.php --backend=2 --verbose --debug --root= --uri= make 1 /vagrant/provision/aegir.make /var/aegir/hostmaster-6.x-2.x

In the process.