PYTHON-1624 Fix failing $out test on MongoDB latest (mongodb#369)

Author: ShaneHarvey

test/test_collection.py

@@ -1616,9 +1616,8 @@ def test_aggregate(self):
  self.assertEqual([{'foo': [1, 2]}], list(result))
 
  # Test write concern.
- out_pipeline = [pipeline, {'$out': 'output-collection'}]
  with self.write_concern_collection() as coll:
- coll.aggregate(out_pipeline)
+ coll.aggregate([{'$out': 'output-collection'}])
 
  def test_aggregate_raw_bson(self):
  db = self.db