DataObject.delete() should either a). not call unset() on "value" properties or b). handle "value" properties as a special case

SEE TUSCANY-1842. The resolution for TUSCANY-1842 is a short-term workaround/hack. This JIRA documents the need for a better, more permanent fix for this problem. Here is the summary of the issue:

It looks like the problem is caused because DataObject.delete() calls unset() on the special "value" property of a wrapper type which causes an invalid instance to be serialized:

<objectsToAttach xsi:type="sev:ValueType"/>

Your hack works around the issue by forcing the loader to accept the invalid instance.

A better fix would be to prevent DataObject.delete() from calling unset() on "value" properties, but there is currently no way to detect that a property is one of these special wrapper value properties. So, I guess your hack is as good as any for now, but we need to document the fact that this is a temporary fix. In the future we need to ensure that unset() is not called - or it has special behavior - for the value properties.