[VOL-4359] Added ETCD data cleanup verification after device delete

Change-Id: Ic3e3eced67826c6c7277cc8c21f0e6241b7e9a0b
diff --git a/tests/scale/Voltha_Scale_Tests.robot b/tests/scale/Voltha_Scale_Tests.robot
index 7dcc4e8..8f6e667 100755
--- a/tests/scale/Voltha_Scale_Tests.robot
+++ b/tests/scale/Voltha_Scale_Tests.robot
@@ -64,6 +64,7 @@
 ${BBSIM_REST_PORT}    50071
 
 ${NAMESPACE}      default
+${INFRA_NAMESPACE}      default
 
 # Scale pipeline values
 ${stackId}  1