spec: fix f28 rpm without firewalld zone
    
    Commit 3b71f2e42d added spec handling for with_firewalld_zone. We
    now call %firewalld_reload if with_firewalld is set. But the matching
    'BuildRequires: firewalld-filesystem' is only applied if
    with_firewalld_zone is set.
    
    Fix the former bit to use with_firewalld_zone
    
    Reviewed-by: Laine Stump <laine@laine.org>
    Reported-by: Yuval Turgeman <yturgema@redhat.com>
    Signed-off-by: Cole Robinson <crobinso@redhat.com>