Support remote_collector and aggregator in cluster

When deployed in a cluster, the remote_collector and aggregator
services are only started when the node holds the virtual IP address.
diff --git a/metadata/service/aggregator/single.yml b/metadata/service/aggregator/single.yml
index 476536c..159e5bd 100644
--- a/metadata/service/aggregator/single.yml
+++ b/metadata/service/aggregator/single.yml
@@ -8,6 +8,7 @@
     nagios_host_dimension_key: nagios_host
   heka:
     aggregator:
+      automatic_starting: true
       enabled: true
       influxdb_time_precision: ms
       poolsize: ${_param:aggregator_poolsize}