'Hook called when registering a class.
This method takes care of adding the class to cinder.objects namespace.
Should registering class have a method called cinder_ovo_cls_init it
will be called to support class initialization.  This is convenient
for all persistent classes that need to register their models.'

def registration_hook(self, cls, index):

    setattr(objects, cls.obj_name(), cls)
    if callable(getattr(cls, 'cinder_ovo_cls_init', None)):
        cls.cinder_ovo_cls_init()
