SHOW DATABASES returns duplicates

[stuartcarnie]

What

When there are multiple DB/RP mappings with the same database name, SHOW DATABASES incorrectly returns duplicates. Note telegraf appears twice in the following results:

{
  "results": [
    {
      "statement_id": 0,
      "series": [
        {
          "name": "databases",
          "columns": [
            "name"
          ],
          "values": [
            [
              "chronograf"
            ],
            [
              "potato"
            ],
            [
              "potatoctl"
            ],
            [
              "telegraf"
            ],
            [
              "telegraf"
            ]
          ]
        }
      ]
    }
  ]
}

This results in duplicates in Chronograf 1.x: