Update test setup to use redfish error log purging

Change-Id: I640fd32ea5597d61e0f46f6a2dcf2c20cf743824
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/redfish/systems/test_thermal_ambient_temperatures.robot b/redfish/systems/test_thermal_ambient_temperatures.robot
index 5837c96..be4212c 100755
--- a/redfish/systems/test_thermal_ambient_temperatures.robot
+++ b/redfish/systems/test_thermal_ambient_temperatures.robot
@@ -11,7 +11,7 @@
 
 Suite Setup         Suite Setup Execution
 Suite Teardown      Suite Teardown Execution
-Test Setup          Delete All Error Logs
+Test Setup          Redfish Purge Event Log
 Test Teardown       Test Teardown Execution