Respect comments about inspector_keep_ports

The previous behaviour did not match the comments.

Change-Id: Ifc7bb3e34a0d8aaa6a6c2dc534f3b9603b1a76ab

ansible/roles/kolla-openstack/templates/kolla/config/ironic-inspector.conf

@@ -13,8 +13,7 @@ add_ports = {{ kolla_inspector_add_ports }}
 {% endif %}
 
 {% if kolla_inspector_keep_ports %}
-# Keep only those ports that were found during inspection.
-keep_ports = present
+keep_ports = {{ kolla_inspector_keep_ports }}
 {% endif %}
 
 # Store logs returned by the inspection ramdisk.

releasenotes/notes/respect-comment-for-keep-ports-e0b1ab73395055a6.yaml

+---
+upgrade:
+  - |
+    If you have customized ``inspector_keep_ports``, ensure it is set to one of:
+    ``all``, ``present``, ``added``.
+fixes:
+  - |
+    ``inspector_keep_ports`` can be set to one of: ``all``, ``present``,
+    ``added``. The previous behavior was to set this to ``present`` if the
+    variable was changed to any non-None value. This respects the behavior
+    indicated in the comments.