exchange: check for remote refs to determine if we're cloning The exchange.pull wrapper function was checking whether any paths were configured yet as a proxy to determine whether we're doing the initial clone or a subsequent pull. Core hg @ bdae51a83dfb (released in 4.5) now sets the 'default' path on the ui object before exchange.pull is called, but we can check a bit more directly by checking if we have any remote refs yet. This is the same as a check we do in GitHandler.fetch_pack().