projman #22960 Uncatched exception when task is defined without a "None" role [resolved]

Traceback:

File "/----/projman/writers/projman_writer.py", line 55, in write_schedule_as_xml
root = schedule_as_dom(project)
File "/----/projman/writers/projman_writer.py", line 81, in schedule_as_dom
begin, end = project.get_task_date_range(task)
File "/----/projman/lib/project.py", line 311, in get_task_date_range
raise ValueError('Task %s has no begin' % (task.id,))
ValueError: Task t22 has no begin