Drop flavors in publish_distro config for leap15.5

[lkocman]

• They're not really used for anything later anyway and only cause issue on renames, etc.

[codecov-commenter]

Codecov Report

Patch and project coverage have no change.

Comparison is base (db6249f) 28.46% compared to head (a286b20) 28.46%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2941 +/- ## ======================================= Coverage 28.46% 28.46% ======================================= Files 84 84 Lines 14512 14512 ======================================= Hits 4131 4131 Misses 10381 10381 ``` Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openSUSE). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openSUSE)

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