Update to power on system before reading voltages

Signed-off-by: Marissa Garza <garzam@us.ibm.com>
Change-Id: I6a1fa8db3488c3f6f53dfe6412be216bfa4b781e
diff --git a/redfish/systems/test_power_voltage_readings.robot b/redfish/systems/test_power_voltage_readings.robot
index 7922418..cbd60a1 100755
--- a/redfish/systems/test_power_voltage_readings.robot
+++ b/redfish/systems/test_power_voltage_readings.robot
@@ -67,6 +67,7 @@
     [Documentation]  Do test case setup tasks.
 
     Printn
+    Redfish Power On  stack_mode=skip
     Redfish.Login