Comment 3 for bug 1855319

This issue is caused by the update of openstack client/neutron client/neutron_lib, but the manage-cleaning-network.sh in ironic-manage-cleaning-network job is not updated accordingly.

The ironic-manage-cleaning-network job is running in openstack heat container.
In starlingx/stx-heat:rc-2.0-centos-stable-20191005T150558Z.0, the version of the clients are:
openstack client: 3.18.0
neutron client: 6.12.0
neutron lib: 1.25.0
'openstack network show baremetal -f value -c subnets' returns an empty string if there are no subnets.

While in starlingx/stx-heat:master-centos-stable-20191119T000000Z.0
openstack client: 4.0.0
neutron client: 6.14.0
neutron lib: 1.29.1
'openstack network show baremetal -f value -c subnets' returns an empty array '[]', but the shell script does not consider '[]' as empty. As a result, the following command leads to an error.