Add pacemaker_hostname to astute.yaml

[Bogdan Dobrelya]

Put 'uname -n' output as pacemaker_hostname parameter into astute.yaml.
We need this option to be able to filter all node names from fuel settings, e.g.
$fqdns = filter_hash($::fuel_settings['nodes'], 'fqdn')
$names = = filter_hash($::fuel_settings['nodes'], 'pacemaker_hostname')

[Bogdan Dobrelya (bogdando)]

superceeded by BP https://blueprints.launchpad.net/fuel/+spec/ha-pacemaker-improvements