add dispatch no-number

dsmz-match.py

@@ -92,6 +92,8 @@ class BacDiveEntry:
         return None
 
     def _dispatch(self, ncbi_taxa):
+        if len(self.strain_number) == 0:
+            return 'no-number', None
         for n in itertools.chain(self.strain_number, self.complete_name):
             taxid = self._match(ncbi_taxa, n, 'no rank')
             if taxid is not None: