Fixing the test failure on python 3.3
Fixing the test failure on python 3.3

magaman384/mongomock,StarfishStorage/mongomock,chartbeat-labs/mongomock,vmalloc/mongomock,drorasaf/mongomock,julianhille/mongomock,mdomke/mongomock,akun/mongomock,marcinbarczynski/mongomock