Updated openstack/openstack
Project: openstack/ceilometer  601fb4b477a3f4cf685f3b8c88d03e5553b4bac3

XenAPI support: Disk rates

Implemented inspect_disk_rates() to inspect the disk statistics as rates
for an instance.

Change-Id: I0220e612b156a967745ff281ce09329fa0d15a12
Implements: blueprint xenapi-support