Fix test teardown directive duplicate in suite

Changes:
    - Setting 'Test Teardown' is allowed only once.
      Updated the directive syntax.

Tested:
     - NA
Change-Id: Ie16888008cdb3870a48aa23dc41ec38e81305aa8
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/redfish/account_service/test_ipmi_redfish_user.robot b/redfish/account_service/test_ipmi_redfish_user.robot
index d2e12c3..f6fc417 100644
--- a/redfish/account_service/test_ipmi_redfish_user.robot
+++ b/redfish/account_service/test_ipmi_redfish_user.robot
@@ -10,7 +10,7 @@
 Test Setup       Test Setup Execution
 Test Teardown    Test Teardown Execution
 
-Test Teardown    IPMI_Redfish_User
+Test Tags        IPMI_Redfish_User
 
 *** Variables ***