Redfish login fix

Description:This checkin provides the fix for redfish
            login/logout issue

Change-Id: Idea4602697b973b576a47760975b31486f0f0297
Signed-off-by: Sushma M M <sushmm99@in.ibm.com>
diff --git a/ipmi/test_ipmi_sensor.robot b/ipmi/test_ipmi_sensor.robot
index 22ef170..a20be12 100644
--- a/ipmi/test_ipmi_sensor.robot
+++ b/ipmi/test_ipmi_sensor.robot
@@ -201,6 +201,7 @@
 
     ${ipmi_reading}=  Get IPMI Power Reading
 
+    Redfish.Login
     ${power}=  Redfish.Get Properties  /redfish/v1/Chassis/chassis/Power
     ${redfish_reading}=  Set Variable  ${power['PowerControl'][0]['PowerConsumedWatts']}