IPMI: Fix for verify Empty SEL

Changes:
    - In ipmi/test_ipmi_sel.robot
    - Added Redfish Power Off step before creating PEL log.

Tested: -Ran above test case from sandbox successfully
Change-Id: Ida8af6304de5625b9b90bd743201bc9db2075170
Signed-off-by: Nandish-Matti <nandish.matti@ibm.com>
diff --git a/ipmi/test_ipmi_sel.robot b/ipmi/test_ipmi_sel.robot
index 13540ec..189660d 100644
--- a/ipmi/test_ipmi_sel.robot
+++ b/ipmi/test_ipmi_sel.robot
@@ -34,6 +34,8 @@
     [Documentation]  Verify IPMI sel clear command clears the SEL entry.
     [Tags]  Verify_Empty_SEL
 
+    Redfish Power Off  stack_mode=skip
+
     # Generate an error log and verify there is one at least.
     Create Test PEL Log
     ${resp}=  Run IPMI Standard Command  sel elist last 1