Added Redfish login and logout for required test.

Changes:
    - Added Redfish login and logout in test cases of
      Verify_Installed_LDAP_Certificate

Tested:
    - Ran test successfully from sandbox gui/gui_test/security_and_access_menu/test_certificates_sub_menu.robot

Change-Id: I8a47713ff3dca27ca1c2be49ddfac19a6e72dfcd
Signed-off-by: rramyasr-in <rramyasr@in.ibm.com>
diff --git a/gui/gui_test/security_and_access_menu/test_certificates_sub_menu.robot b/gui/gui_test/security_and_access_menu/test_certificates_sub_menu.robot
index c261a19..d1755b5 100644
--- a/gui/gui_test/security_and_access_menu/test_certificates_sub_menu.robot
+++ b/gui/gui_test/security_and_access_menu/test_certificates_sub_menu.robot
@@ -109,11 +109,13 @@
     [Documentation]  Install LDAP certificate via Redfish and verify it in GUI.
     [Tags]  Verify_Installed_LDAP_Certificate
 
+    Redfish.Login
     Delete Certificate Via BMC CLI  Client
 
     # Install LDAP certificate.
     ${file_data}=  Generate Certificate File Data  Client
     Install And Verify Certificate Via Redfish  Client  Valid Certificate Valid Privatekey  ok
+    Redfish.Logout
 
     # Refresh GUI and verify certificate is available in GUI.
     Refresh GUI