fixing variable to import voltha test library

Change-Id: I4889afbe0fef05d2531d431dafc6d57102b3c591
diff --git a/src/test/cord-api/Tests/WorkflowValidations/SIAB.robot b/src/test/cord-api/Tests/WorkflowValidations/SIAB.robot
index 731b6d5..a1c07a7 100644
--- a/src/test/cord-api/Tests/WorkflowValidations/SIAB.robot
+++ b/src/test/cord-api/Tests/WorkflowValidations/SIAB.robot
@@ -23,7 +23,7 @@
 Library           OperatingSystem
 Library           XML
 Library           RequestsLibrary
-Library           %{HOME}/voltha/tests/atests/common/testCaseUtils.py
+Library           ${WORKSPACE_DIR}/voltha/tests/atests/common/testCaseUtils.py
 Library           ../../Framework/utils/utils.py
 Resource          ../../Framework/utils/utils.robot
 Library           ../../Framework/restApi.py
@@ -36,6 +36,7 @@
 Variables         ../../Properties/RestApiProperties.py
 
 *** Variables ***
+${WORKSPACE_DIR}           /home/cord
 ${WHITELIST_PATHFILE}      ${CURDIR}/data/SIABWhitelist.json
 ${SUBSCRIBER_PATHFILE}     ${CURDIR}/data/SIABSubscriber.json
 ${VOLT_DEVICE_PATHFILE}    ${CURDIR}/data/SIABOLTDevice.json