Fix: Transaction integrity on create_relation

[chrisbc]

This GT has not linked the 16 subtasks correctly. But no failure observed in client side ??

query q0 {
  node(id: "R2VuZXJhbFRhc2s6MTA3Mjc=") {
    ... on GeneralTask {
      title
      created
      children {
        total_count
        edges {
          node {
            child_id
            child {
              ... on AutomationTask {
                id
              }
            }
          }
        }
      }
    }
  }
}

query q30 {
  node(id: "QXV0b21hdGlvblRhc2s6MTA3Mjg=") { #10728
  #node(id: "QXV0b21hdGlvblRhc2s6MTA3MzA=") { #10730
  #node(id: "QXV0b21hdGlvblRhc2s6MTA3NDI=") { #10742 Yes
  #node(id: "QXV0b21hdGlvblRhc2s6MTA3NDM=") { #10743 404
    id
    ... on AutomationTask {
      parents {
        total_count
        edges {
          node {
            parent {
              id
            }
          }
        }
      }
    }
  }
}

[chrisbc]

getting global ids ...

[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from graphql_relay.node.node import *
>>> to_global_id("A", 1)
'QTox'
>>> to_global_id("AutomationTask", 10728)
'QXV0b21hdGlvblRhc2s6MTA3Mjg='
>>> to_global_id("AutomationTask", 10729)
'QXV0b21hdGlvblRhc2s6MTA3Mjk='