Comment 4 for bug 1849004

I thing there is a bug in MyCache.py :

`if res.scheme == "https" and res.username != "":`

The value of `res.username` is `None` when it is not set, not the empty string.

Code from UpdateManager/Core/MyCache.py :

```
    def _get_changelog_or_news(self, name, fname, strict_versioning=False,
                               changelogs_uri=None):
        " helper that fetches the file in question "
    ...
        # https uris are not supported when they contain a username/password
        # because the urllib2 https implementation will not check certificates
        # and so its possible to do a man-in-the-middle attack to steal the
        # credentials
        res = urlsplit(uri)
        if res.scheme == "https" and res.username != "":
            raise HttpsChangelogsUnsupportedError(
                "https locations with username/password are not"
                "supported to fetch changelogs")
```