Some OpenStack installer such as [1] use power reset when switching
from bootstrap kernel to OS installation kernel. So we'd better
implement this.
[1] https://review.openstack.org/#/admin/projects/openstack/daisycloud-core
Change-Id: I60df3a31c7600d35d50212538fbfffd22bf7c729
Signed-off-by: Zhijiang Hu <hu.zhiiang@zte.com.cn>