Use static dnssec-root.key with link from lib
    
    Points to static data, which would be overwritten by
    unbound-anchor.service. Makes default key kept intact and dynamic data
    put instead of symlink.
    
    Ignore most of file properties of %_localstatedir/unbound/root.key,
    default symlink is replaced with anchor maintained regular file.
    
    Resolves: rhbz#2132103