Automation fix for Network sub menu

Changes:
    - Modified "Delete DNS Servers And Verify" keyword
    - Modified "Add DNS Servers And Verify"
    - Removed "DNS Test Setup Execution" keyword from
      redfish/managers/test_bmc_network_conf.robot
      and added in lib/bmc_network_utils.robot

Tested:
    - Ran successfully
      gui/gui_test/settings_menu
      /test_network_sub_menu.robot
      gui/lib/gui_resource.robot
      lib/bmc_network_utils.robot
      redfish/managers/test_bmc_network_conf.robot

Change-Id: I6ffcb7aba29312fa1e4cc843453bca49cd44d0f1
Signed-off-by: Megha G N <Megha.G.N@ibm.com>
diff --git a/gui/gui_test/settings_menu/test_network_sub_menu.robot b/gui/gui_test/settings_menu/test_network_sub_menu.robot
index a7e800b..8a83246 100644
--- a/gui/gui_test/settings_menu/test_network_sub_menu.robot
+++ b/gui/gui_test/settings_menu/test_network_sub_menu.robot
@@ -129,7 +129,9 @@
     [Documentation]  Login to GUI Network page, add DNS server IP
     ...  and verify that the page reflects server IP.
     [Tags]  Configure_And_Verify_DNS_Server_Via_GUI
-    [Teardown]  Delete DNS Servers And Verify
+    [Setup]  DNS Test Setup Execution
+    [Teardown]  Run Keywords  Delete Static Name Servers  AND
+    ...  Configure Static Name Servers
 
     Add DNS Servers And Verify  ${dns_server}
 
@@ -240,7 +242,11 @@
     Wait Until Page Contains Element  ${xpath_add_dns_ip_address_button}  timeout=15
     # Check if all name servers deleted on BMC.
     ${nameservers}=  CLI Get Nameservers
-    Should Be Empty  ${nameservers}
+    Should Not Contain  ${nameservers}  ${original_nameservers}
+
+    DNS Test Setup Execution
+
+    Should Be Empty  ${original_nameservers}
 
 
 Add Static IP Address And Verify
diff --git a/gui/lib/gui_resource.robot b/gui/lib/gui_resource.robot
index 4a22f34..d53091d 100644
--- a/gui/lib/gui_resource.robot
+++ b/gui/lib/gui_resource.robot
@@ -194,6 +194,9 @@
     ${cli_name_servers}=  CLI Get Nameservers
     ${cmd_status}=  Run Keyword And Return Status
     ...  List Should Contain Sub List  ${cli_name_servers}  ${dns_server}
+    Run Keyword If  '${expected_status}' == '${HTTP_OK}'
+    ...  Should Be True  ${cmd_status} == ${True}
+    ...  ELSE  Should Not Be True  ${cmd_status}
 
 
 Navigate To Server Power Page