This removes usage of deprecated Ceilometer API
1. Changing trigger type from "OS::Ceilometer::Alarm"
to "OS::Aodh::GnocchiAggregationByResourcesAlarm"
2. Add "resource_type" fixed with value "instance"
3. Change some paramters (meter_name-> metric,
statistic ->aggregation_method, period-> granularity)
4. Change value from "average" to "mean" in method to
compare to the threshold
Change-Id: I486c14cbc9d05a0e826bbef1ad181bdcb2d8c951
Closes-Bug: #1735484