The monkey patch for urllib.request._urlopener does nothing on Python 3.

(cherry picked from commit f1589378)
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Status Job ID Name Coverage
  External
passed SlapOS.Buildout.UnitTest-Master.Python2

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passed SlapOS.Buildout.UnitTest-Master.Python3

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passed SlapOS.Buildout.UnitTest-Master.Python2

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passed SlapOS.Buildout.UnitTest-Master.Python3

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