Sort metric data before grouping and processing
Sort metric data before grouping and processing

In gnocchi dispatcher, metric data will be grouped by resource_id and
counter_name before processing. But the inputted data is an unordered
list. It is better being sorted by resource_id and counter_name before
processing.

Change-Id: I8f493f720c479fd84b1a554ee5196115b992ecd1

cernops/ceilometer,ityaptin/ceilometer,mathslinux/ceilometer,r-mibu/ceilometer,idegtiarov/ceilometer,fabian4/ceilometer,eayunstack/ceilometer,ityaptin/ceilometer,mathslinux/ceilometer,redhat-openstack/ceilometer,r-mibu/ceilometer,openstack/ceilometer,fabian4/ceilometer,isyippee/ceilometer,eayunstack/ceilometer,maestro-hybrid-cloud/ceilometer,redhat-openstack/ceilometer,idegtiarov/ceilometer,openstack/ceilometer,isyippee/ceilometer,cernops/ceilometer,maestro-hybrid-cloud/ceilometer