Devstack changes to ceilometer to support vsphere

Ceilometer currently supports only libvirt when installed
using devstack. Have extended this support to Vmware Vsphere in this changelist.

Change-Id: I98c64204973bca5e6a7f859a5431adb2b661277f
Merge "Devstack changes to ceilometer to support vsphere"
Merge branch 'master' of github.com:openstack-dev/devstack