This makes a small change on the failed-migration path.  Up to now,
all VMs that failed non-live migration after the "stop" command
were restarted.  This must not be done when the VM was paused in
the first place.

* src/qemu/qemu_driver.c (qemudDomainMigratePerform): Do not restart
  a paused VM that fails migration.  Set paused state after "stop",
  reset it after failure.