slapos_cloud: fixup allocation supply cell upgrade/consistency check

- Support Slave Instance allocated in the same tree
- allow creating allocation consistency ticket on Instance Node
- handle allocation consistency for Slave Instance without Instance Node
16 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
failed SlapOS-Master.UnitTest-Master

02:24:02

failed SlapOS.Eggs.UnitTest-Master.Python2

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failed SlapOS.Eggs.UnitTest-Master.Python3

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failed SlapOS-Master.UnitTest-Master

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failed SlapOS-Master.UnitTest-Master

02:33:54

failed SlapOS-Master.UnitTest-Master

02:17:39

failed SlapOS.Eggs.UnitTest-Master.Python2

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failed SlapOS.Eggs.UnitTest-Master.Python2

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failed SlapOS.Eggs.UnitTest-Master.Python2

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failed SlapOS.Eggs.UnitTest-Master.Python2

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failed SlapOS.Eggs.UnitTest-Master.Python2

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failed SlapOS.Eggs.UnitTest-Master.Python3

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failed SlapOS.Eggs.UnitTest-Master.Python3

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failed SlapOS.Eggs.UnitTest-Master.Python3

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failed SlapOS.Eggs.UnitTest-Master.Python3

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failed SlapOS.Eggs.UnitTest-Master.Python3

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