remotemetadata cleanup

- dont overwrite metadata if lookup does not return anything
- make find fail without error

oml/item/models.py

@@ -321,6 +321,7 @@ class Item(db.Model):
         logger.debug('scrape %s', primaryid)
         if primaryid:
             m = meta.lookup(*primaryid)
+            if m:
                 m['primaryid'] = primaryid
                 self.meta = m
         self.update()

oml/metaremote.py

@@ -23,7 +23,7 @@ def request(action, data):
 
 def find(query):
     logger.debug('find %s', query)
-    return request('findMetadata', {'query': query})['items']
+    return request('findMetadata', {'query': query}).get('items', [])
 
 def lookup(key, value):
     logger.debug('lookup %s %s', key, value)