kojiwrapper: Make result of runroot world readable
    
    The commands in runroot run as root every time. If they create files
    that are not readable to other users, the reset of compose could have
    problems with it if it does not run as root too. Particularly updates
    composes in Bodhi run under apache user.
    
    Relates: https://pagure.io/pungi/issue/932
    Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>