downloader: check return value from progresscb
downloader: check return value from progresscb

bgamari/librepo,Tojaj/librepo,cgwalters/librepo,rpm-software-management/librepo,rholy/librepo,rpm-software-management/librepo,cgwalters/librepo,rholy/librepo,cgwalters/librepo,rpm-software-management/librepo,rholy/librepo,Tojaj/librepo,Conan-Kudo/librepo,Conan-Kudo/librepo,Tojaj/librepo,bgamari/librepo,rholy/librepo,bgamari/librepo,Conan-Kudo/librepo,cgwalters/librepo