Adjust metering time units to sometime use a smaller unit

[Doug Fish]

While reviewing https://review.openstack.org/#/c/96800 it seemed to me the code would sometimes select a larger time unit that people would normally use to describe the data.

Consider these 2 representations of 2 data sets

Data set 1a: 15 sec 30 sec 45 sec 30 sec 75 sec
Data set 1b: .2 min .5 min .7 min 1.2 min

Data set 2a : 1 day 2 days 3 days 10 days 13 days
Data set 2b: .1 weeks .3 weeks .4 weeks 1.4 weeks 1.9 weeks

IMO the "a" version is how people normally think about the data, yet the metering unit code will select "b".

Specifically I think the metering time unit selection code should not move to the next higher unit at 1 unit, but instead should convert at 2 or 3 units.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/130336

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/130336
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=4f15492980d7573f17eb8a5a5584944ce54f2dac
Submitter: Jenkins
Branch: master

commit 4f15492980d7573f17eb8a5a5584944ce54f2dac
Author: Doug Fish <email address hidden>
Date: Wed Nov 19 20:44:43 2014 -0600

    Update metering unit selection to use smaller units for time

    Update the unit selection to not convert to a higher unit until
    the max value is at least 2 units.

    Change-Id: I349b328b553ed634a70b70b695d4db92295c9b67
    Closes-bug: #1384248