wrong rating of ip.floating service when collector= gnocchi

Environment based on Kolla/Ubuntu/Ocata/CK 5.0.1

Each floating IP allocated to a project, generates 3 events in gnocchi. For example, if I have 2 floating IP allocated to project, I get this info stored in gnocchi:

# gnocchi metric list | grep floating
| 02cb79a8-693d-4b76-b463-771b1ca9b1a2 | low | ip.floating.create | 4f2deb40-970e-4b5a-a627-ccc8ecdc2e72 |
| 1971143e-1f41-4819-ab2d-f6628e7b38b4 | low | ip.floating.update | 4f2deb40-970e-4b5a-a627-ccc8ecdc2e72 |
| 4c8d8f6c-f62c-4113-8e3e-92c2e146fa61 | low | ip.floating.create | 74e61639-56d8-48d8-b2ba-f87d86b940c9 |
| b7c01692-0ff0-41c5-8465-af34d57dc9a7 | low | ip.floating | 74e61639-56d8-48d8-b2ba-f87d86b940c9 |
| c8232694-799f-48f9-b034-233e1325f635 | low | ip.floating.update | 74e61639-56d8-48d8-b2ba-f87d86b940c9 |
| fd8514e1-0f12-4aef-a6b0-d0a8d05cf512 | low | ip.floating | 4f2deb40-970e-4b5a-a627-ccc8ecdc2e72 |

So, now, cloudkitty reports two different resources, and each reasource has 3 units:

| 2017-10-11T15:42:00 | 2017-10-11T15:43:00 | 6f47a4723d3241438cfe1e76a1429f1a | [{u'volume': u'3', u'rating': u'3.0', u'service': u'network.floating', u'desc': {u'created_by_user_id': u'2827e162f00a4742b509a4f92fc7c74e', u'project_id': u'6f47a4723d3241438cfe1e76a1429f1a', u'revision_start': u'2017-10-11T14:21:58.717829+00:00', u'revision_end': None, u'ended_at': None, u'resource_id': u'4f2deb40-970e-4b5a-a627-ccc8ecdc2e72', u'type': u'network', u'created_by_project_id': u'008b131d0faf42dc89a167ae6425d057', u'original_resource_id': u'4f2deb40-970e-4b5a-a627-ccc8ecdc2e72', u'user_id': None, u'ip.floating': 3.0, u'started_at': u'2017-10-11T14:21:58.717816+00:00', u'creator': u'2827e162f00a4742b509a4f92fc7c74e:008b131d0faf42dc89a167ae6425d057', u'id': u'4f2deb40-970e-4b5a-a627-ccc8ecdc2e72'}}] |
| 2017-10-11T15:42:00 | 2017-10-11T15:43:00 | 6f47a4723d3241438cfe1e76a1429f1a | [{u'volume': u'3', u'rating': u'3.0', u'service': u'network.floating', u'desc': {u'created_by_user_id': u'2827e162f00a4742b509a4f92fc7c74e', u'project_id': u'6f47a4723d3241438cfe1e76a1429f1a', u'revision_start': u'2017-10-11T14:33:58.668664+00:00', u'revision_end': None, u'ended_at': None, u'resource_id': u'74e61639-56d8-48d8-b2ba-f87d86b940c9', u'type': u'network', u'created_by_project_id': u'008b131d0faf42dc89a167ae6425d057', u'original_resource_id': u'74e61639-56d8-48d8-b2ba-f87d86b940c9', u'user_id': None, u'ip.floating': 3.0, u'started_at': u'2017-10-11T14:33:58.668645+00:00', u'creator': u'2827e162f00a4742b509a4f92fc7c74e:008b131d0faf42dc89a167ae6425d057', u'id': u'74e61639-56d8-48d8-b2ba-f87d86b940c9'}}]

In short, CK reports 6 ip.floating units, but should report just 2.