Improve ovs cleanup utility help
Improve ovs cleanup utility help

Fixed a couple of things for ovs_all_ports=False.
First state that it also cleans up ports created by Nova.
Second since [1] it only cleans up the integration bridge.

[1] https://opendev.org/openstack/neutron/commit/b09b4460

Change-Id: I41dda554e8cb4b4ca36515d64f17ad5bf52f3b49
Closes-Bug: #1853582

openstack/neutron,mahak/neutron,mahak/neutron,openstack/neutron,openstack/neutron,mahak/neutron