Mistral loses context of some tasks in error cases

[Oleg Ovcharuk]

Mistral loses context of some tasks in case there are errors in workflow execution.
Let me show 2 examples:

join_context_example:
  tasks:
    b1:
      action: std.noop
      publish:
        context:
          b1: 1
      on-success: join_task
    join_task:
      action: std.noop
      join: all
      publish:
        context:
          join_task: 2
      publish-on-error:
        context:
          join_task: 1
    bs:
      action: std.noop
      publish:
        context:
          bs: 1
      on-success:
        - b2
        - b3
    b2:
      action: std.noop
      publish:
        context:
          b2: 1
      on-success: join_task
    b3:
      action: std.fail
      publish-on-error:
        context:
          b3: 1
      on-success: join_task

Expected context:
{\"bs\": 1, \"b2\": 1, \"b1\": 1, \"join_task\": 1, \"b3\": 1}
Actual context:
{\"b1\": 1, \"join_task\": 1, \"bs\": 1, \"b3\": 1}

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/mistral 17.0.0.0rc1 release candidate.