'Make a object representation compatible with target version.'

def obj_make_compatible(self, primitive, target_version):

    super(VolumeAttachment, self).obj_make_compatible(primitive, target_version)
    target_version = versionutils.convert_version_to_tuple(target_version)
    if (target_version < (1, 2)):
        primitive.pop('connection_info', None)
