with items concurrency doesn't work if value is YAQL

[Winson Chan]

vagrant@arkham:~/tmp$ cat ~/tmp/test-repeat-batch.yaml
---
version: "2.0"
wfc:
  type: direct
  input:
    - batch_size
  tasks:
    task1:
      with-items: i in [1, 2, 3, 4, 5, 6]
      concurrency: <% $.batch_size %>
      action: std.echo output=<% $.i %>

vagrant@arkham:~/tmp$ mistral workflow-create ~/tmp/test-repeat-batch.yaml
+------+--------+------------+----------------------------+------------+
| Name | Tags | Input | Created at | Updated at |
+------+--------+------------+----------------------------+------------+
| wfc | <none> | batch_size | 2015-08-22 00:18:47.017157 | None |
+------+--------+------------+----------------------------+------------+

vagrant@arkham:~/tmp$ mistral workflow-list
+---------------------+--------+------------------------------+----------------------------+------------+
| Name | Tags | Input | Created at | Updated at |
+---------------------+--------+------------------------------+----------------------------+------------+
| std.delete_instance | <none> | instance_id | 2015-08-22 00:16:37.185521 | None |
| std.create_instance | <none> | name, image_id, flavor_id... | 2015-08-22 00:16:37.265245 | None |
| wfc | <none> | batch_size | 2015-08-22 00:18:47.017157 | None |
+---------------------+--------+------------------------------+----------------------------+------------+

vagrant@arkham:~/tmp$ mistral execution-create wfc '{"batch_size": 2}'
ERROR (app) unsupported operand type(s) for +: 'int' and 'unicode'
Traceback (most recent call last):

  File "/opt/openstack/mistral/.venv/local/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 142, in _dispatch_and_reply
    executor_callback))

  File "/opt/openstack/mistral/.venv/local/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 186, in _dispatch
    executor_callback)

  File "/opt/openstack/mistral/.venv/local/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 129, in _do_dispatch
    result = func(ctxt, **new_args)

  File "/home/vagrant/code/openstack/mistral/mistral/engine/rpc.py", line 98, in start_workflow
    **params

  File "/home/vagrant/code/openstack/mistral/mistral/utils/__init__.py", line 106, in _logged
    return func(*args, **kw)

  File "/home/vagrant/code/openstack/mistral/mistral/engine/default_engine.py", line 94, in start_workflow
    raise e

TypeError: unsupported operand type(s) for +: 'int' and 'unicode'

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/217127

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/217127
Committed: https://git.openstack.org/cgit/openstack/mistral/commit/?id=920b25ffc72360cc7f5d16e38da388ee994d1421
Submitter: Jenkins
Branch: master

commit 920b25ffc72360cc7f5d16e38da388ee994d1421
Author: Nikolay Mahotkin <email address hidden>
Date: Wed Aug 26 16:04:25 2015 +0300

    Fixing working concurrency when value is YAQL

    Closes-Bug: #1487651

    Change-Id: I45abd0c064f4e1be9aee86f4488281ecb9830a62