Reboot task updated
Reboot task updated

Compute nodes reboot task changed from shell command to reboot plugin task
to address bug FPL-167.

Change-Id: Ic16882f29a9ecdc920a719144f4ce39c06a7d99e

zioc/fuel-plugin-contrail,stackforge/fuel-plugin-contrail,andrei4ka/fuel-plugin-contrail,stackforge/fuel-plugin-contrail,andrei4ka/fuel-plugin-contrail,zioc/fuel-plugin-contrail,zioc/fuel-plugin-contrail,andrei4ka/fuel-plugin-contrail,stackforge/fuel-plugin-contrail,stackforge/fuel-plugin-contrail