cayenne-lifecycle: UuidBatchFault concurrency issues

In case of UuidRelationship, when one thread is fetching the source entity, it may override UuidBatchFault of the existing objects. Then when another thread tries to read object relationship, it triggers fault resolution, all in parallel with the first thread, so ConcurrentModificationException may happen between UuidBatchFault.addUuid() and UuidBatchFault.fetchObjects().