Vdb conversion should exclude model 'checksum' and 'index' properties

Conversion of an xmi vdb to a dynamic vdb simply copies all properties contained in models. However, this includes both the 'checksum' and 'indexName' properties which are not applicable to dynamic vdbs. Worse still this is counter-productive since the Dynamic Vdb Sequencers in Komodo actually use the 'indexName' property to determine if the model is Declarative or not, excluding those models with the property present.