This is caused by caching a pointer and reference to the data cache's
IPersistStorage interface without managing reference counts
appropriately.

Based on a patch by Rob Shearman.

For now we forward the methods to the data cache as before.

both defer to the real data object if the cached versions fail and we
are running.

Cleanup DefaultHandler_GetCanonicalFormatEtc by using
This->pDataDelegate instead of querying for IDataObject from
This->pOleDelegate.

ole32: Tell the advise holder what the data delegate is in DefaultHandle_DAdvise if we are already connected.

As per MSDN, if the object has no connections then
IOleObject::EnumAdvises should return a NULL enumerator and S_OK. This
is the case when This->oleAdviseHolder is NULL, so do this and avert a
potential NULL dereference of This->oleAdviseHolder (found by
Coverity).

delegating to the remote IOleObject_DoVerb function.

data change notifications.