Description of problem:
Values collected for Network I/O for a VM are always 0, even during download of a huge file.

Version-Release number of selected component (if applicable):
CFME 5.8.4.1
RHV 4.2.2.5

How reproducible:
100 %

Steps to Reproduce:
1. Have a CFME appliance, VM on RHV and working C&U collection.
2. SSH to your VM and cd to /tmp.
3. On your VM: wget --no-check-certificate releases.manageiq.org/manageiq-ovirt-gaprindashvili-2.ova
4. Now SSH to your appliance and enter rails console (rails c).
5. Find your provider (rhevm = ManageIQ::Providers::Redhat::InfraManager.find_by(:name => "rhv_cfme_integration"))
6. Find your VM (my_vm = rhevm.vms.find_by(:name => "vm_snapshot_3"))
7. Monitor collected statistics on net usage (my_vm.perf_collect_metrics('realtime', 1.minute.ago))

Actual results:
The result is always :net_usage_rate_average=>0.0

Expected results:
The download speed reported by wget utility for me was 2 MB/s so I would expect to see similar values.