Use {{ ansible_fqdn }} for service checks

Some of these checks are for services running on a physical host
(nova-compute for example), and as such we need to use
{{ ansible_fqdn }} rather than {{ ansible_hostname }}.

Closes #452

(cherry picked from commit d7216eccb6e7733f1079e09d99b04ca58634da19)
Merge pull request #464 from claco/proposed/juno

backport - proposed/juno - Use {{ ansible_fqdn }} for service checks