996925 - Exception while deleting manifest

The error is caused by the refresh pools. If a bonus pool is deleted before
the source pool, the deletion of the source pool causes the error in the trace.

Also cleaned up the annotations as both javax.persistence.CascadeType.ALL and
hibernate.CascadeType.ALL were used on the same relationship. This has been shown
to cause conflicts. Removed the hibernate.CascadeType.MERGE because it is redundant.