lib: fix distribute-list deletion (backport #16551)

[mergify]

When a whole distribute-list is deleted (can be done only using API), all its children must be cleaned up manually.

Fixes #16538

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This is an automatic backport of pull request #16551 done by Mergify.

[mergify]

Cherry-pick of 8fad4f3 has failed:

On branch mergify/bp/stable/9.0/pr-16551
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Unmerged paths:
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	both modified:   lib/distribute.c

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