DeleteWorkflowExecution is not transactional with workflow completion update

[samarabbas]

When decider responds back with complete workflow decision, we first update the execution with new events and then delete workflow execution as a separate transaction. This can cause issues when the update times out but we successfully apply the update. This can cause us to never delete this workflow execution.
We need to make sure that execution is update and deleted in the same transaction.

[mfateev]

Another option is to schedule a transfer task for delete. It would also work with archival of completed workflows to an external system.

[samarabbas]

This sounds much cleaner approach. Let me code up the fix using transfer task.

[samarabbas]

Fixed.