Reporting start and end are invalid

[ghost]

Looking at the following section of code:

https://github.com/cloudfoundry-incubator/cf-abacus/blob/87dc920ec237683714668162bbb5a12b495116ba/lib/aggregation/reporting/src/index.js#L757-L767

it seems that start has the semantic of the beginning of the month for which a report is requested and end has the semantic of the timestamp up to which the report is requested, or the current time, in case such a timestamp has not been specified.

However, that code executes only if there is no report to be returned. In the happy path, when a report does exist, we use the start and end of the document in the aggregator that contains the values coming from (what I believe) is the last submitted usage.

We should make start and end consistent, where the former case seems to make more sense.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/152798900

The labels on this github issue will be updated when the story is started.