call hy_repo_link when setting the appdata of the system repo
call hy_repo_link when setting the appdata of the system repo

Otherwise our repo data is freed prematurely.

hughsie/libhif,Conan-Kudo/libhif,rpm-software-management/libdnf,rpm-software-management/libhif,hughsie/libhif,edynox/libdnf,hughsie/libhif,cgwalters/libhif,rpm-software-management/libdnf,cgwalters/libhif,Conan-Kudo/libhif,Conan-Kudo/libhif,rpm-software-management/libhif,edynox/libdnf,rpm-software-management/libhif,cgwalters/libhif,hughsie/libhif,Conan-Kudo/libhif,edynox/libdnf,rpm-software-management/libdnf,cgwalters/libhif,rpm-software-management/libhif,edynox/libdnf,rpm-software-management/libdnf