Fix date range selector does not show data of last day when user timezone is not UTC

[hakobera]

Related to #594 and #617.
In following conditions, re:dash does not show the data of last day.

• some timestamp value group by day
• user in non UTC timezone

Like this:

SELECT
  to_char(created_at, 'YYYY-MM-DD') as day,
  COUNT(*) AS cnt
FROM
  queries
GROUP BY
  day
ORDER BY
  day

I think this is caused dateRange is treated as local timezone, but point.x is treated as UTC.
Following screenshot is a result of console.log(dateRange, point.x); before https://github.com/EverythingMe/redash/blob/master/rd_ui/app/scripts/services/resources.js#L197

This pull request fix this issue, but I'm not sure that this change is OK for timezone handling in re:dash.
@arikfr What do you think?

[arikfr]

Are you sure it's due to time zone differences and not because of the time value of the max value? It looks like your fix actually does that: moves the the hour to be of end of day.

What you did looks ok to me, but I will make sure that we indeed create all time values in the same time zone as you mentioned.

Thanks.

[hakobera]

@arikfr Thanks for review. I realized that this is not a issue of the time value of the max value, it's only related timezone difference issue. So I change my code to treat dateRange as UTC, it is as same as point.x.

It shows time as JST (because I live in Japan), and both object's _isUTC is true

Is this OK for you?

[arikfr]

Merged. Thanks!