remove unused MongoQuery attributes

Author: timgraham

django_mongodb/query.py

@@ -43,13 +43,9 @@ class MongoQuery:
 
     def __init__(self, compiler):
         self.compiler = compiler
-        self.connection = compiler.connection
-        self.ops = compiler.connection.ops
         self.query = compiler.query
-        self._negated = False
         self.ordering = []
-        self.collection_name = self.compiler.collection_name
-        self.mongo_query = getattr(compiler.query, "raw_query", {})
+        self.mongo_query = {}
         self.subqueries = None
         self.lookup_pipeline = None
         self.project_fields = None
@@ -63,7 +59,8 @@ def __init__(self, compiler):
     @cached_property
     def collection(self):
         # Initialize this lazily since `compiler.collection` connects to the
-        # database.
+        # database and a connection isn't needed if the query raises
+        # EmptyResultSet.
         return self.compiler.collection
 
     def __repr__(self):