Fix for Test_Power_Reading_Via_IPMI_With_Host_Booted test
Fix for Test_Power_Reading_Via_IPMI_With_Host_Booted test

Changes:
     - Long back we use to have two URI to get power values under
       /redfish/v1/Chassis
     - Now we have a single URI to check power reading
       /redfish/v1/Chassis/chassis/Sensors/total_power.
     - With this commit we have modified logic to use this new
       Redfish power reading URI

Tested: - Ran Test_Power_Reading_Via_IPMI_With_Host_Booted test
       from sandbox successfully.
Change-Id: Ib2292c13510fde39a691bf04bd4f6ec65d35b043
Signed-off-by: Rahul Maheshwari <a806e6fd77e56dd64ff6084a06bbf3a5a70392ef@in.ibm.com>

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