'Get a list of server security groups.
The listing result is an object with property "items". Each item is
security group associated with this server.
Example GET:
http://localhost/api/nova/servers/abcd/security-groups/'

@rest_utils.ajax()
def get(self, request, server_id):

    groups = api.neutron.server_security_groups(request, server_id)
    return {'items': [s.to_dict() for s in groups]}
