Calculate Metering Used Hours only from used metrics in metering reports

[lpichler]

Metric Fixed Compute - is count of metric rollups (=hours) which have at least one non-zeros of chargeable metrics

Metric Used Hours

before
same as Metric Fixed Compute

after
is count of metric rollups (=hours) which have at least one non-zeros of used chargeable metrics
in discussion with @Loicavenel used chargeable metrics are these:
Memory Used, CPU Used and Network I/O Used

@miq-bot add_label bug, gaprindashvili/yes
@miq-bot assign @gtanzillo

Reproducer

1. Manage Provider with metric and enable C&U
2. Create Metering Vm report and add here used chargeable metrics mentioned above at least and metering used hours, fixed metric compute
3. PUT zeros to metric in MetricRollups record for used chargeable metrics metrics
   in rails console e.g.:

# for Oct's rollups
 MetricRollup.where('extract(month from timestamp) = ?', 11).update_all({"cpu_usagemhz_rate_average"=>0, "derived_memory_used"=>0, "net_usage_rate_average"=>0})

4. If all used chargeable metrics are zeroed then Metric Used Hours is zero

cc @nachandr

[lpichler]

@Loicavenel do we have BZ for it ?

[miq-bot]

Checked commit lpichler@bfd22ce with ruby 2.3.3, rubocop 0.47.1, haml-lint 0.20.0, and yamllint 1.10.0
5 files checked, 0 offenses detected
Everything looks fine. 👍

[simaishi]

Gaprindashvili backport details:

$ git log -1
commit fc83d6beb199069d81a72c5ed6f3e5a32da72c88
Author: Gregg Tanzillo <[email protected]>
Date:   Tue Dec 19 10:09:17 2017 -0500

    Merge pull request #16677 from lpichler/metering_used_metric_should_depends_only_on_used_metrics
    
    Calculate Metering Used Hours only from used metrics in metering reports
    (cherry picked from commit 2c9c3c1946f998472edbbc8dbd53477cf873072f)