This option is useful when using Gnocchi with the patch introduced in
https://github.com/gnocchixyz/gnocchi/pull/1059. That patch can
cause queries to return more than one entry per granularity (
timespan), according to the revisions a resource has. This can be
problematic when using the 'mutate' option of Cloudkitty. Therefore,
we proposed this option to allow operators to discard all
datapoints returned from Gnocchi, but the last one in the
granularity queried by CloudKitty. The default behavior is
maintained, which means, CloudKitty always use all of the data
points returned.
Change-Id: I051ae1fa3ef6ace9aa417f4ccdca929dab0274b2
abffd13426