Missing openid_provider_authentication_response() function

Hi,

the function openid_provider_authentication_response() has been deleted (d6 and d7). There is a comment about that by anarcat in another issue and there were some comments in the code (before it had been deleted), i'd like to cite :

- * It is unclear what this function is for. It is not used anywhere,
- * and looks like a "10.1. Positive Assertions", but that's what
- * openid_provider_authentication_response() does...
- *
- * This is basically a copy of openid_redirect_http() but it does a
- * full HTTP request directly from the browser.

This function is used for example by OpenID Provider AX (which is broken right now) and basically tests if the relying party, where to send the attributes to, is available. Of course this could be implemented within the depending AX module, but it might be used by some other modules as well, that's why i guess it was in the OpenID Provider module.

Anyway, the function might not be the best code so far :-) But deleting it breaks depending module(s), so it should not be done without deeper discussion. IMHO it would be the best way to re-add the function to the module and then let's find the best solution.