fix "slapos_pdm: Use upgrade_scope on Computer Node for cleanup enabling"

The change was missing in the commit 439786ba.
5 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
failed SlapOS-Master.UnitTest-Master

01:34:21

passed SlapOS.Eggs.UnitTest-Master.Python2

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passed SlapOS.Eggs.UnitTest-Master.Python3

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failed SlapOS.Eggs.UnitTest-Master.Python2

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passed SlapOS.Eggs.UnitTest-Master.Python3

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