In order to respect the convention [backendtype_backendname]
for all collectors and storage backends in Cloudkitty configuration
some sections names has changed.
* For the Gnocchi collector, [collector_gnocchi] has been added
in addition to [gnocchi_collector].
This last one will be removed in the future.
* For the hybrid storage, [storage_hybrid] has been added
in addition to [hybrid_storage].
This last one will be removed in the future.
* For the keystone fetcher, [fetcher_keystone] has been added
in addition to [keystone_fetcher].
This last one will be removed in the future.
* For the hybrid storage, [fetcher_source] has been added
in addition to [source_fetcher].
This last one will be removed in the future.
* Fix Prometheus section name.
Change-Id: I3435a151de4b384f2f2540225504abe6c99b928e
Story: 2001053
Task: 4654
fb0b176ac7