Check for valid network before probe-create call

Check that a public and/or private network exists before calling
probe-create for it, to avoid an error in the case where that
network hasn't been created

Change-Id: If01cec47dc4ab02b5d78074b1354df10dc23b384
Closes-bug: #1560629
diff --git a/lib/neutron-legacy b/lib/neutron-legacy
index e06a020..34f9840 100644
--- a/lib/neutron-legacy
+++ b/lib/neutron-legacy
@@ -1453,9 +1453,13 @@
 function setup_neutron_debug {
     if [[ "$Q_USE_DEBUG_COMMAND" == "True" ]]; then
         public_net_id=`_get_net_id $PUBLIC_NETWORK_NAME`
-        neutron-debug --os-tenant-name admin --os-username admin --os-password $ADMIN_PASSWORD probe-create --device-owner compute $public_net_id
+        if [[ -n $public_net_id ]]; then
+            neutron-debug --os-tenant-name admin --os-username admin --os-password $ADMIN_PASSWORD probe-create --device-owner compute $public_net_id
+        fi
         private_net_id=`_get_net_id $PRIVATE_NETWORK_NAME`
-        neutron-debug --os-tenant-name admin --os-username admin --os-password $ADMIN_PASSWORD probe-create --device-owner compute $private_net_id
+        if [[ -n $private_net_id ]]; then
+            neutron-debug --os-tenant-name admin --os-username admin --os-password $ADMIN_PASSWORD probe-create --device-owner compute $private_net_id
+        fi
     fi
 }