Hi Philipp,
on Linux I've solved commenting the option in modules.conf file (I think that could remove the perl module itself from <PERL_PATH>/Ocsinventory/Agent/Modules/Download.pm)
#use Ocsinventory::Agent::Modules::Download;
On Windows I've removed the Download.exe file after installation.
In this way I have no need to recompile anything.
I don't think that there's a need to fork as long as this feature has file that are easy to identify.
Regards,
Gabriele