[Orgmode] Do not use hard links on attachments stored in git

[Bernt Hansen]

I keep my org files and attachments in a git repository.  I noticed that
org-mode allows you to hardlink attachments.

I just want to point out that if you put these in a git repository then
I don't recommend using the hardlink option.  Git breaks hardlinks and
you'll end up with two versions of the attachment.

Regards,
Bernt