Add hard reboot for outputting console log

If a instance backup, the console log file is truncated and we cannot
get any console log through "console-log" API.
To avoid this problem, this patch adds a hard reboot call for outputting
some console log.

Related-Bug: #1251920
Change-Id: Ic41ee9e12beb3277a1095933c81016336057111f
Merge "Add hard reboot for outputting console log"