Magic macros in the destination URL don't work with 3rd party click tracking (ct0)

> From https://developer.openx.org/jira/browse/OX-6023

If the ct0 parameter is supplied (i.e. when 3rd party click tracking is enabled), any magic macro present in the banner destination URL isn't replaced.

Comment from Erik:
> We've tested this "in the field" today and I can confirm that this change fixes the issue.
> 
> We thank our client EuroRelais (see: http://www.eurorelais.nl/ ) for funding the development and testing of this fix.