Fix: DHCPv6 Fix for Delete IPV6 Address Keyword

Changes:
   Fix: DHCPv6 fix for valid_status_code

Tested:
   Ran and tested on BMC Environment.

Change-Id: I3cfd293ca7ccafdd605f3a58cf1a494d6542ee27
Signed-off-by: Sweta Potthuri <spotthur@in.ibm.com>
diff --git a/redfish/managers/test_bmc_ipv6.robot b/redfish/managers/test_bmc_ipv6.robot
index 53c14f6..0bb72b1 100644
--- a/redfish/managers/test_bmc_ipv6.robot
+++ b/redfish/managers/test_bmc_ipv6.robot
@@ -369,7 +369,7 @@
     ${ethernet_interface}=  Set Variable  ${active_channel_config['${CHANNEL_NUMBER}']['name']}
 
     Redfish.patch  ${REDFISH_NW_ETH_IFACE}${ethernet_interface}  body=&{data}
-    ...  valid_status_codes=[${HTTP_OK},${HTTP_ACCEPTED},${HTTP_NO_CONTENT}]
+    ...  valid_status_codes=${valid_status_codes}
 
     # Note: Network restart takes around 15-18s after patch request processing
     Sleep  ${NETWORK_TIMEOUT}s