This reverts commit c7ffa6c2.

the assumptio of this change was that this would not break
any existing machine. Andrey Borzenkov reported troubles with
the ACPI reboot method: the system would hang on reboot, necessiating
a power cycle. Probably more systems are affected as well.

Also, there are patches queued up for v2.6.29 to disable virtualization
on emergency_restart() - which was the original motivation of
this change.
Reported-by: NAndrey Borzenkov <arvidjaar@mail.ru>
Bisected-by: NAndrey Borzenkov <arvidjaar@mail.ru>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Acked-by: NAvi Kivity <avi@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>