Re: [referrer-policy-tests] Replace a use of cStringIO with StringIO to avoid a problem with old Python versions, (#4457)

Notifying @kristijanburnik. *([Learn how reviewing works](https://github.com/w3c/web-platform-tests/blob/master/README.md#test-review).)*

View on GitHub: https://github.com/w3c/web-platform-tests/pull/4457#issuecomment-270146529

Received on Tuesday, 3 January 2017 15:55:00 UTC