Graphite: use adaptive time calculation.
Graphite: use adaptive time calculation.

If the graphite interval is shorter than the update period for the
service being submitted, graphite will register discontinuities. Still,
we prefer to offer accurate state times whenever possible, so simply
submitting the current time isn't always the best option.

We now submit the original state's time UNLESS interval has already
elapsed--in which case we use the current time.

aphyr/ustate