update playbook syntax for Ansible 2.4
update playbook syntax for Ansible 2.4

(I deployed using this the other week (and then manually started the server in
screen, since adapting the Upstart script to Systemd looked nontrivial) and
forgot to check in the change)

FoxLisk/Leafline,zackmdavis/Leafline,FoxLisk/Leafline,FoxLisk/Leafline,zackmdavis/Leafline,zackmdavis/Leafline,zackmdavis/Leafline,FoxLisk/Leafline