Added keyword Clean Up All Nodes to kill stale lxc processes in Suite Teardown

Change-Id: Iac5367cb5eb6158a1897ff05ff2fa1f77a6e3111
diff --git a/tests/functional/Voltha_ScaleFunctionalTests.robot b/tests/functional/Voltha_ScaleFunctionalTests.robot
index 58e6a8e..709336e 100755
--- a/tests/functional/Voltha_ScaleFunctionalTests.robot
+++ b/tests/functional/Voltha_ScaleFunctionalTests.robot
@@ -196,6 +196,7 @@
     Run Keyword If    ${teardown_device}    Execute ONOS CLI Command use single connection    ${ONOS_SSH_IP}    ${ONOS_SSH_PORT}
     ...    device-remove ${of_id}
     Close All ONOS SSH Connections
+    Run Keyword If    ${has_dataplane}    Clean Up All Nodes
 
 Clean Up Linux
     [Documentation]    Kill processes and clean up interfaces on src+dst servers