Added keyword to execute command on XCAT.
Added keyword to execute command on XCAT.

Resolves openbmc/openbmc-test-automation#811

Change-Id: Id99156b1a2fb591eb01354bccb31652cde879197
Signed-off-by: Rahul Maheshwari <a806e6fd77e56dd64ff6084a06bbf3a5a70392ef@in.ibm.com>

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