Revert "Fix stack failure when default subnetpool is set"

This reverts commit 8a3b7d424d8edf53d0560db48247e6bca11176ee.

This change masked a non-backward compatible change made to the
Neutron core API. This is being cleaned up and thus this workaround
is no longer required.

Depends-on: Idf516ed9db24d779742cdff0584b48182a8502d6

Change-Id: I6695a6e17df1a395ada4ecf2b063b2c20870d99d
diff --git a/exercises/neutron-adv-test.sh b/exercises/neutron-adv-test.sh
index 9bcb766..a8fbd86 100755
--- a/exercises/neutron-adv-test.sh
+++ b/exercises/neutron-adv-test.sh
@@ -235,7 +235,7 @@
     local NET_ID
     NET_ID=$(neutron net-create --tenant-id $TENANT_ID $NET_NAME $EXTRA| grep ' id ' | awk '{print $4}' )
     die_if_not_set $LINENO NET_ID "Failure creating NET_ID for $TENANT_ID $NET_NAME $EXTRA"
-    neutron subnet-create --ip-version 4 --tenant-id $TENANT_ID --gateway $GATEWAY --subnetpool None $NET_ID $CIDR
+    neutron subnet-create --ip-version 4 --tenant-id $TENANT_ID --gateway $GATEWAY $NET_ID $CIDR
     neutron_debug_admin probe-create --device-owner compute $NET_ID
     source $TOP_DIR/openrc demo demo
 }