review inclusion of mmdvocab

[ferrighi]

Inclusion of vocab does not seem to be working (https://github.com/metno/solr-indexer/blob/master/solrindexer/indexdata.py#L146)

[ferrighi]

To me it seems that the vocabulary is not initialized. But I do not think it suitable to same query for each single file to index.