Added Redfish login and logout for required test suites

Changes:
    - Added Redfish login and logout in suite setup and teardown
      of test_snmp_alerts_sub_menu.robot suite.
    - Added Redfish login and logout in test cases of
      test_network_sub_menu.robot and test_ldap_sub_menu.robot

Tested:
    - Ran successfully all test modified test cases from sandbox.

Change-Id: I51062feddd469ce2989c31289f34e9d38facfb91
Signed-off-by: Rahul Maheshwari <rahulmaheshwari@in.ibm.com>
diff --git a/gui/gui_test/security_and_access_menu/test_ldap_sub_menu.robot b/gui/gui_test/security_and_access_menu/test_ldap_sub_menu.robot
index e413b56..a184c08 100644
--- a/gui/gui_test/security_and_access_menu/test_ldap_sub_menu.robot
+++ b/gui/gui_test/security_and_access_menu/test_ldap_sub_menu.robot
@@ -73,6 +73,8 @@
 Verify LDAP Configurations Editable
     [Documentation]  Verify LDAP configurations are editable.
     [Tags]  Verify_LDAP_Configurations_Editable
+    [Setup]  Redfish.Login
+    [Teardown]  Redfish.Logout
 
     Create LDAP Configuration  ${LDAP_SERVER_URI}  ${LDAP_TYPE}  ${LDAP_BIND_DN}
     ...  ${LDAP_BIND_DN_PASSWORD}  ${LDAP_BASE_DN}