Make OMB work if the configured domain name does not exclusively contain lower case...

Make OMB work if the configured domain name does not exclusively contain lower case letters.

If the configured domain is mixed-case OAuth throws invalidsignature errors. The current URL is part of the signated parts; since the consumer does not pass the current URL, the service has to get it itself and add it to the other OAuth params for signature rebuilding. OAuth.php uses $_SERVER for this, however, the domain is lcased in $_SERVER. Hence we pass the complete current URL as generated by common_local_url to OAuthRequest.