Correct the docstring for _should_enable_unknown_hosts
Correct the docstring for _should_enable_unknown_hosts

We open for unknown hosts if either:
 node_not_found_hook is set OR some node is introspected

This matches the method in iptables driver:
ttps://opendev.org/openstack/ironic-inspector/src/branch/master/ironic_inspector/pxe_filter/iptables.py#L33-L38

Change-Id: I4fa06fb879e5d55a383820a52f4ffc7c4b1134a2

openstack/ironic-inspector,openstack/ironic-inspector