added the import of the utils.connection_string function in the mongodb_datasource main.py module

plugins/mongodb_datasource/main.py

@@ -12,7 +12,7 @@ import urllib
 from lodel import logger
 
 from .utils import mongodbconnect, object_collection_name, \
-    connect, MONGODB_SORT_OPERATORS_MAP
+    connect, MONGODB_SORT_OPERATORS_MAP, connection_string
 
 class MongoDbDataSourceError(Exception):
     pass