This reverts commit 8e6d5d404cf49e5b68b43c62e7f6d7db2771a1f4.
As detailed in the bug, this is overly racy, waiting for the event
potentially a long ways (and a couple RPC calls) away from where
the event will be triggered. The compute manager now has a generic
mechanism to do this which conflicts and replaces this functionality,
if enabled (default is off in Rocky, to be defaulted to on in Stein).
Conflicts:
nova/tests/unit/virt/libvirt/test_driver.py
nova/virt/libvirt/driver.py
Change-Id: Ibf2b5eeafd962e93ae4ab6290015d58c33024132
Closes-Bug: #1786346