Invalid HTTP response when trying to access a ZIP archive of private repo while logged out.

ZenDesk ticket: https://gitlab.zendesk.com/agent/tickets/15148

When trying to download an archived ZIP of a private repo without being authenticated an invalid response error is thrown.

@jacobvosmaer quickly pointed out on Slack that he thinks the problem is that the headers say the body is gzipped, but what you get is uncompressed text.

/cc @ayufan