Generated Reports' status completed timestamp indicator is incorrect

[elasticmachine]

Original comment by @ppf2:

Take the latest generated reports page from this instance as an example.

!LINK REDACTED

It says 9/13 4:30pm (Pacific) as the report added time, and under Status, it shows another timestamp under the status "Completed" as 9/13 4:31pm (also Pacific) - which suggests to the end user that it completed at 9/13 4:31pm.

But if I query the .reporting index sorted by latest completed_at, it returns different times (payload and output removed else it's too much text).

{
  "took": 6,
  "timed_out": false,
  "_shards": {
    "total": 4,
    "successful": 4,
    "failed": 0
  },
  "hits": {
    "total": 4,
    "max_score": null,
    "hits": [
      {
        "_index": ".reporting-2016.09.11",
        "_type": "esqueue",
        "_id": "it242khl000813a009ftwuut",
        "_score": null,
        "_source": {
          "jobtype": "printable_pdf",
          "priority": 10,
          "created_by": "pius",
          "timeout": 240000,
          "process_expiration": "2016-09-13T23:35:47.022Z",
          "created_at": "2016-09-13T23:30:12.153Z",
          "attempts": 1,
          "max_attempts": 3,
          "status": "completed",
          "started_at": "2016-09-13T23:31:47.022Z",
          "completed_at": "2016-09-13T23:33:41.514Z"
        },
        "sort": [
          1473809621514
        ]
      },

Notice that the completed at time is actually 9/13 4:33pm, which is +2 mins from what is specified on the UI.

If the issue here is that we are reporting only the started_at time, then this becomes a request to provide potentially 3 time indicators, report creation time, start time, and completed time to avoid confusion :)

Also, while we are on this topic, if we start displaying reports from all users on the generated reports page in the future, it will be nice to start displaying these timestamps including seconds information to be more granular.