Adding keywords to do host power off & on using external IPMI.
Adding keywords to do host power off & on using external IPMI.

Resolves openbmc/openbmc-test-automation#521

Change-Id: I7ddae02a0ef81a7dccea2d215e076049f2a707e1
Signed-off-by: Sridevi Ramesh <cb5e1f81dd390dfc3a9afc08ab7298b7ab4296f5@in.ibm.com>

openbmc/openbmc-test-automation,openbmc/openbmc-test-automation