build-pkgs --reuse rebuilds some packages even without source changes

[Luis Sampaio]

Brief Description
-----------------

build-pkgs --reuse is rebuilding packages even though there are no source changes.

Severity
--------
Major: reuse feature

Steps to Reproduce
------------------

1 - Create "Source" environment

initialized the env
downloader
build-pkgs
build-image
copied the deb-local-build and deb-local-source to webserver

2 - Created another env to work as destination environment

initialized the env
downloader (it should download the same binaries as the source env)
build the packages:

export STX_SHARED_REPO="http://<URL>/deb-local-build/"
export STX_SHARED_SOURCE="http://<URL>/deb-local-source/"

build-pkgs --reuse

35 std packages were rebuilt but the source code is the same as the source env so I think there may be some issue.

All packages that were rebuilt have the log saying:

shared_cheksum for these shows as "None"

Expected Behavior
------------------
No packages should be rebuilt without source changes

Actual Behavior
----------------
Some packages are rebuilt

Reproducibility
---------------
Yes

Last Pass
---------
NA.

Timestamp/Logs
--------------
NA

Workaround
--------------
NO

[Luis Sampaio (lsampaio)]

It looks like the checksum is correct in the file so it may be a problem with the code that loads the checksums and verifies if it matches (source vs dest)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/root/+/868005

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/root/+/868005
Committed: https://opendev.org/starlingx/root/commit/7b957158bbaffd22848f757d967e8dea58d54f21
Submitter: "Zuul (22348)"
Branch: master

commit 7b957158bbaffd22848f757d967e8dea58d54f21
Author: Luis Sampaio <email address hidden>
Date: Fri Dec 16 13:12:03 2022 -0800

    Reuse fix to not rebuild if no source changes

    build-pkgs --reuse rebuilds some packages even without source
    changes. This commit fixes the checksum comparison which was
    not working correctly for all package paths.

    Test Plan:
    Pass: build-pkgs --reuse and no packages were rebuilt
    Pass: build-pkgs (no packages were rebuilt)
    Pass: make changes to 1 package and call build-pkgs to
    rebuild it
    Pass: build-pkgs --clean (rebuilds all local packages)

    Closes-Bug: 1999941
    Signed-off-by: Luis Sampaio <email address hidden>
    Change-Id: Id93a692f6a69212967453e42809e66595ae01f59