core:delete_async_tasks_and_compensation_data...

delete_async_tasks_and_compensation_data.sql exits on KeyError

Adding a CASCADE to the TRUNCATE commands to force tables cleanup.

Change-Id: I097bf1f388f082f768cd50c33d11ea1e9f081004
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=949229
Signed-off-by: Eli Mesika <emesika@redhat.com>