On a recent mosci run the guest used for a restart test had a
pending power task which stopped the restart test working properly.
This PR adds an assertion that the guest is ready.
* Add method for deleteing pacemaker nodes.
* Due to LP #1874719 use above to delete node1
* During test cleanup the tests re-enable hosts from a masakari pov,
if that host still has outstanding notifications it will fail so
retry the enable.
* pacemakerd process name has changed on focal so account for that
when killing it.