patch for #334333

[Thomas Lange]

Sorry, my last patch did not work. The Perl code is very difficult to
understand. This patch works, so now grub is also added when calling fai-mirror.

pittermaennche[~]> diff fai-2.8.4/scripts/install_packages .
315a316,317
>   @complete = grep {!/-$/} @complete if $opt_d; # ignore packages ending with - when using -d
> 

Please verify the patch.

-- 
regards Thomas