Executions and action_executions remain unremoved after functional testing

[Lingxian Kong]

After functional testing, there are a lot of executions and action executions unremoved in the system, which were created during testing.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/216322

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/216509

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/216322
Committed: https://git.openstack.org/cgit/openstack/mistral/commit/?id=5bd01b7bfbb38e4d0ff9839499ba44aea346e50e
Submitter: Jenkins
Branch: master

commit 5bd01b7bfbb38e4d0ff9839499ba44aea346e50e
Author: Lingxian Kong <email address hidden>
Date: Tue Aug 25 00:14:34 2015 +0800

    Purge executions created during functional testing

    Change-Id: Ibcfbe23d2608d43a21e7a5b77002071672325fa9
    Partial-Bug: #1488157

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/216509
Committed: https://git.openstack.org/cgit/openstack/mistral/commit/?id=f2eaea5a126e21b2b6fe2649855a8556d4d15ef5
Submitter: Jenkins
Branch: master

commit f2eaea5a126e21b2b6fe2649855a8556d4d15ef5
Author: Lingxian Kong <email address hidden>
Date: Tue Aug 25 10:54:51 2015 +0800

    Support action_execution deletion

    With this patch, users can perform operation as following:
    DELETE http://127.0.0.1:8989/v2/action_executions/<action_execution_id>

    NOTE:
    * Added a new config item 'allow_action_execution_deletion', with default
      value 'False'.
    * The 'allow_action_execution_deletion' item is set to 'True' for
      functional testing.
    * Only ad-hoc action-execution can be deleted.
    * Only completed action execution can be deleted.

    Implements: blueprint mistral-action-execution-deletion
    Closes-Bug: #1488157
    Change-Id: I3729636911a42c273c5a7b2d7fbdaae0da398e31