keystone.users.check_in_group throws exception instead of False

[Mike Lowe]

When calling keystone.users.check_in_group it will return True for status 204 as per the api but throws a keystoneclient.exceptions.NotFound: Not Found (HTTP 404) when it should return false. The api documentation states that a 404 return code means a user is not in a group and does not indicate an error. Briefly reviewing the documentation I think it is safe and expected for BaseManager.head(...) from python-keystoneclient/keystoneclient/openstack/common/apiclient/base.py to return False for a 404 error code. Something like this is more appropriate:

    def _head(self, url):
        """Retrieve request headers for an object.
        :param url: a partial URL, e.g., '/servers'
        """
        try:
           resp = self.client.head(url)
           return resp.status_code == 204
        except keystoneclient.exceptions.NotFound:
            return False

[Steve Martinelli (stevemar)]

Unfortunately I think this is a backwards incompatible change.