Divide by zero can occur when querying non-active VM

[Drew Thorstensen]

 [-] float division by zero
 Traceback (most recent call last):
   File "/usr/lib/python2.7/dist-packages/powervc_nova/virt/ibmpowervm/pvm/driver.py", line 488, in monitor_instances
     instance_obj, duration=None)
   File "/usr/lib/python2.7/dist-packages/ceilometer_powervm/compute/virt/powervm/inspector.py", line 199, in inspect_cpu_util
     util = float(util_cap + util_uncap - idle - donated) / float(entitled)
 ZeroDivisionError: float division by zero

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/220843
Committed: https://git.openstack.org/cgit/stackforge/ceilometer-powervm/commit/?id=1885f85438b38a952cbf0313ff079d18e50809e8
Submitter: Jenkins
Branch: master

commit 1885f85438b38a952cbf0313ff079d18e50809e8
Author: Drew Thorstensen <email address hidden>
Date: Sun Sep 6 15:48:13 2015 -0400

    Handle unstarted instances

    In the rare event that a VM is queried for CPU utilization before its
    first boot, the entitled cycles may be 0. This resulted in a divide by
    zero error. This change detects that scenario and removes the divide by
    zero possibility.

    Change-Id: If37422e7b501c60ad2b1cb610b8c7802e6543942
    Closes-Bug: 1492831