Valid exceptions during provider login causes unrecoverable exception

[robinharms]

Sorry for the cryptic title :P

Basically, if you create an OpenID login form and post "dummy" as URL, it causes an exception rather than sending you to the authentication error screen. This is probably true for other login providers, but it's extremely bad for OpenID since exceptions aren't handled in anyway.

Basically, everything during OpenIDConsumer.login -process should be catched i think.