SEBA-571 setting onu_state field as a variable in test library

Change-Id: I100157350a1daa36e515076f402ec6ef1aff6c3d
diff --git a/src/test/cord-api/Framework/ATTWorkFlowDriver.robot b/src/test/cord-api/Framework/ATTWorkFlowDriver.robot
index d7f4e8b..e280aaf 100644
--- a/src/test/cord-api/Framework/ATTWorkFlowDriver.robot
+++ b/src/test/cord-api/Framework/ATTWorkFlowDriver.robot
@@ -22,6 +22,9 @@
 Library           ../Framework/utils/utils.py
 Library           ../Framework/restApi.py
 
+*** Variable ***
+${ONU_STATE_VAR}    onu_state
+
 *** Keywords ***
 Service Instance Status Check
     [Arguments]    ${onu_device}
@@ -30,7 +33,7 @@
     Log    ${json_result}
     ${json_result_list}=    Get From dictionary    ${json_result}    items
     ${getJsonDict}=    utils.getDictFromListOfDict    ${json_result_list}    serial_number    ${onu_device}
-    ${onu_state}=  Get From Dictionary    ${getJsonDict}   onu_state
+    ${onu_state}=  Get From Dictionary    ${getJsonDict}   ${ONU_STATE_VAR}
     ${authentication_state}=  Get From Dictionary    ${getJsonDict}   authentication_state
     ${status_message}=  Get From Dictionary    ${getJsonDict}   status_message
     [Return]    ${onu_state}    ${authentication_state}    ${status_message}