SecurityTestCase: generate assertUserCanNot... methods

the "failIf..." naming scheme is deprecated in unittest, we should at
least have new-style named methods
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passed ERP5.CodingStyleTest-Master

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passed ERP5.PerformanceTest-Master

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failed ERP5.UnitTest-Master

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failed ERP5.UnitTest-Master.Medusa

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passed SlapOS.Eggs.UnitTest-Master.Python2

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passed SlapOS.Eggs.UnitTest-Master.Python3

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failed ERP5.UnitTest-Master

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passed SlapOS.Eggs.UnitTest-Master.Python2

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passed SlapOS.Eggs.UnitTest-Master.Python2

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passed SlapOS.Eggs.UnitTest-Master.Python2

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passed SlapOS.Eggs.UnitTest-Master.Python3

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passed SlapOS.Eggs.UnitTest-Master.Python3

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passed SlapOS.Eggs.UnitTest-Master.Python3

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