Removed single data center restriction for VMware

The single data center restriction no longer applies for the VMware
compute driver.

Change-Id: I151d4831a74f92c57cd98b96fb0b405d3061b832
backport: havana
Change Nova configuration key 'libvirt_type' to 'virt_type'

The configuration key 'libvirt_type' became 'virt_type' under the
[libvirt] section in nova.conf on Icehouse.

Change-Id: Ib6c4df9a518c8637b36ca1dff67fbbbdc2eb78e5
Closes-Bug: #1287878
3PAR: Update docs to reflect backend assisted volume migrate support

This change updates the 3PAR documentation to reflect new support
for backend assisted volume migrate, which was added in change Ia42503d4

Change-Id: I05e5b5cbe90531fd4e829ca3e200f9542261dfa8
Merge "Change Nova configuration key 'libvirt_type' to 'virt_type'"
Merge "3PAR: Update docs to reflect backend assisted volume migrate support"
Merge "Removed single data center restriction for VMware"