Fix the heka grains for the aggregator/remote_collector

Previously, the heka salt grains of the node running aggregator/remote_collector
get all the metric_collector alarms from all nodes (/etc/salt/grains.d/heka).
The resulting mines data is then wrong for the monitoring node, while that
situtation fortunately has no impact regarding metric_collector alarm
configurations, the Nagios service leverging mine data get a wrong list of
alarms for the monitoring node.

This patch fixes the issue with minimal changes but it appears that the logic
behind _service.sls state is not optimal and become hard to understand.
This state is executed several times with different contexts for every heka
'server' types and is not indempotent, indeed the /etc/salt/grains.d/heka file
content is different between 'local' servers (metric|log)_collector and
'remote' servers remote_collector|aggregator.
1 file changed