• Fix st2 execution get command so now --attr argument correctly works with child
  properties of the result and trigger_instance dictionary (e.g. --attr result.stdout result.stderr). (bug fix)
• Update traces list API endpoint and st2 trace list so the traces are sorted by
  start_timestamp in descending order by default. This way it's consistent with executions
  list and -n CLI parameter works as expected. (improvement)
• Allow users to specify sort order when listing traces using the API endpoint by specifying
  ?sort_desc=True|False query parameters and by passing --sort=asc|desc parameter to
  the st2 trace list CLI command. (improvement)
• Fix a bug with action default parameter values not supporting Jinja template
  notation for parameters of type object. (bug fix, improvement)
• Fix --user / -u argument in the st2 key delete CLI command.
• Retry connecting to RabbitMQ on services start-up if connecting fails because
  of an intermediate network error or similar. (improvements)