Fix to accommodate fault LED string change.

 -System Fault LED string changed from "fault" to "rear_fault"
  recently

Resolves openbmc/openbmc-test-automation#700

Change-Id: I90059b832acd30d761a58954f54fed34d301373f
Signed-off-by: Sweta Potthuri <spotthur@in.ibm.com>
diff --git a/tests/test_led.robot b/tests/test_led.robot
index 33dd53c..ca20788 100644
--- a/tests/test_led.robot
+++ b/tests/test_led.robot
@@ -55,8 +55,8 @@
 Test Fault LED And Verify Via REST
     [Documentation]  Turn On/Off fault LED and verify via REST.
     # LED Name  LED State
-    fault       On
-    fault       Off
+    rear_fault       On
+    rear_fault       Off
 
     [Tags]  Test_Fault_LED_And_Verify_Via_REST
     [Template]  Set System LED State