Address issue for deprecated syntax

Change from :FOR to FOR/END to address a new WARNING in
the new robot version.

Sample warning message as mention below.

FOR loop starting on line 26: For loop header
':FOR' is deprecated. Use 'FOR' instead.

Change-Id: I3860386614d8418f10291977654976929f534b69
Signed-off-by: Sushil Singh <susilsi7@in.ibm.com>
diff --git a/redfish/managers/test_bmc_network_conf.robot b/redfish/managers/test_bmc_network_conf.robot
index 3d82259..eedbaec 100644
--- a/redfish/managers/test_bmc_network_conf.robot
+++ b/redfish/managers/test_bmc_network_conf.robot
@@ -59,22 +59,25 @@
     [Documentation]  Get IP Address And Verify.
     [Tags]  Get_IP_Address_And_Verify
 
-    : FOR  ${network_configuration}  IN  @{network_configurations}
-    \  Verify IP On BMC  ${network_configuration['Address']}
+    FOR  ${network_configuration}  IN  @{network_configurations}
+      Verify IP On BMC  ${network_configuration['Address']}
+    END
 
 Get Netmask And Verify
     [Documentation]  Get Netmask And Verify.
     [Tags]  Get_Netmask_And_Verify
 
-    : FOR  ${network_configuration}  IN  @{network_configurations}
-    \  Verify Netmask On BMC  ${network_configuration['SubnetMask']}
+    FOR  ${network_configuration}  IN  @{network_configurations}
+      Verify Netmask On BMC  ${network_configuration['SubnetMask']}
+    END
 
 Get Gateway And Verify
     [Documentation]  Get gateway and verify it's existence on the BMC.
     [Tags]  Get_Gateway_And_Verify
 
-    : FOR  ${network_configuration}  IN  @{network_configurations}
-    \  Verify Gateway On BMC  ${network_configuration['Gateway']}
+    FOR  ${network_configuration}  IN  @{network_configurations}
+      Verify Gateway On BMC  ${network_configuration['Gateway']}
+    END
 
 Get MAC Address And Verify
     [Documentation]  Get MAC address and verify it's existence on the BMC.
@@ -91,9 +94,10 @@
     [Documentation]  Verify all configured IP and netmask on BMC.
     [Tags]  Verify_All_Configured_IP_And_Netmask
 
-    : FOR  ${network_configuration}  IN  @{network_configurations}
-    \  Verify IP And Netmask On BMC  ${network_configuration['Address']}
-    ...  ${network_configuration['SubnetMask']}
+    FOR  ${network_configuration}  IN  @{network_configurations}
+      Verify IP And Netmask On BMC  ${network_configuration['Address']}
+      ...  ${network_configuration['SubnetMask']}
+    END
 
 Get Hostname And Verify
     [Documentation]  Get hostname via Redfish and verify.