Duplicated config options with merge kolla config feature

[Will Szumski]

Steps to reproduce:

- symlink config file present in base config into environment subdirectory e.g ln -s ../../kolla/config/nova.conf .
- Observe duplicated content in merged configuration files

This happens because the contents of one file is merged with itself.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/kayobe/+/900059

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/kayobe/+/900059
Committed: https://opendev.org/openstack/kayobe/commit/2f4b45cd17ca348f699cdcf6a3e63e3d3cc35184
Submitter: "Zuul (22348)"
Branch: master

commit 2f4b45cd17ca348f699cdcf6a3e63e3d3cc35184
Author: Will Szumski <email address hidden>
Date: Fri Nov 3 17:42:35 2023 +0000

    Stop merging config when symlink points to same file

    This can result in duplicated configuration options.

    Change-Id: I4dd6ffae027345b8c1cc217a63e85f8af7fc9746
    Closes-Bug: #2042689

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/2023.1
Review: https://review.opendev.org/c/openstack/kayobe/+/900317

[OpenStack Infra (hudson-openstack)]

Change abandoned by "Mark Goddard <email address hidden>" on branch: stable/2023.1
Review: https://review.opendev.org/c/openstack/kayobe/+/900317
Reason: Not on antelope

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/kayobe/+/901336

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/kayobe/+/901336
Committed: https://opendev.org/openstack/kayobe/commit/786a78d074a4451cf2774b2e8e4c0808816beff2
Submitter: "Zuul (22348)"
Branch: master

commit 786a78d074a4451cf2774b2e8e4c0808816beff2
Author: Will Szumski <email address hidden>
Date: Fri Nov 17 18:56:23 2023 +0000

    Deduplicate before picking merge strategy

    I missed this when I refactored the code to fallback
    to templating. We need to deduplicate before picking
    the strategy for the fallback to work for symlinked files.

    Change-Id: Iddd6c90a6daa41e1d1cdaa6b598491792c13394d
    Closes-Bug: #2042689

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/kayobe 15.0.0.0rc1 release candidate.