The metrics had problem with the points, if I post/save a metric point
that is created in the future, it was selected.
Example:
It is 10:00 am, I post or save a metric point and it's 'created at'
10:30 am. Using the "Last 12 hours" the metric point would be selected.
This update is applied on all the SQL queries, on minutes, hours, days.
Related to CachetHQ/Cachet#2848