Let's notify provider_ax about the profile changes in order to get support for update_url (AX) functionality.
Basically all is needed:

module_invoke('openid_provider', 'update', $node->uid);

It's not important to pass back the new values, openid_provider_sreg will collect it.
See #506072: Notify provider_ax about the profile changes,, same purpose but for openid_cp_field