carbonara: retrieve unaggregated timeserie only once for upgrade
carbonara: retrieve unaggregated timeserie only once for upgrade

The unaggregated timeserie was retrieve for each archive policy
aggregation method and definition, which is useless. Once is enough.

Change-Id: I83002ed1f49c8b50eb56f698a9af17a333ceac4f

gnocchixyz/gnocchi,sileht/gnocchi,leandroreox/gnocchi,sileht/gnocchi,gnocchixyz/gnocchi,leandroreox/gnocchi