VMware: Set target ESX host for backing VM clone

The backing VM corresponding to a volume is cloned during create volume
from another volume, snapshot or image. The backing VM is also cloned
during retype and backup restore. Currently, the target ESX host is
unset while calling vCenter CloneVM_Task API and hence the source ESX
host is used as the target. If the destination datastore returned by
the datastore selection logic is not accessible to the source host,
clone fails. This patch fixes the problem by setting the target ESX
host (returned by datastore selection logic) while invoking clone.

Closes-Bug: #1380602
Change-Id: I030d5ce6378fb70f7f98356114825abc12297687
Merge "VMware: Set target ESX host for backing VM clone"