Prefixes stub URLs like 'user@hostname:user/repo.git' with 'ssh://'.
        That's required because although they use SSH they sometimes don't
        work with a ssh:// scheme (e.g. GitHub). But we need a scheme for
        parsing. Hence we remove it again afterwards and return it as a stub.

def get_url_rev_and_auth(self, url):
        """
        Prefixes stub URLs like 'user@hostname:user/repo.git' with 'ssh://'.
        That's required because although they use SSH they sometimes don't
        work with a ssh:// scheme (e.g. GitHub). But we need a scheme for
        parsing. Hence we remove it again afterwards and return it as a stub.
        """
        if '://' not in url:
            assert 'file:' not in url
            url = url.replace('git+', 'git+ssh://')
            url, rev, user_pass = super(Git, self).get_url_rev_and_auth(url)
            url = url.replace('ssh://', '')
        else:
            url, rev, user_pass = super(Git, self).get_url_rev_and_auth(url)

        return url, rev, user_pass