task timestamps are not based on when the task callback is run

[sfromm]

The timestamp for a task is not based on when the task runs. It appears to be when the plugin was initialized.

> select starttime, endtime from playbook where id = 10765;
2013-06-06 06:10:02.322810|2013-06-06 06:14:56.600461
> select id, timestamp, module, result from task where playbook_id = 10765;
153369|2013-06-06 06:10:02.318206|setup|OK
153370|2013-06-06 06:10:02.318206|copy|OK
153372|2013-06-06 06:10:02.318206|command|OK
153374|2013-06-06 06:10:02.318206|command|OK
153375|2013-06-06 06:10:02.318206|command|OK
153394|2013-06-06 06:10:02.318206|wait_for|OK
153395|2013-06-06 06:10:02.318206|command|OK

[sfromm]

Fixed with d7664ed4