fix kvm issue, for windows sever 2008, it will crash without hyperv enlightment featre enabled
There are few cases that mgt server won't reponse agent's pingcommand timely, or in KVM's case, libvirt won't repsonse in few mintues, which will cause agent reconnect to mgt server, then all the on going tasks on host will fail
remove unused XS plugins
don't need to check if pv driver is updated, old pv driver should work
CLOUDSTACK-7762 -[Automation] - Fix test failure for test_02_revert_vm_snapshots in smoke/test_vm_snapshots.py