fix chown on linux/debian

the package creation fails (for me) if scripts/linux/debian/DEBIAN is owned by root, so I restrict the chown to scripts/linux/debian/usr.
I created a similar patch before (which did a bit too much I think), this was reverted by some other patch, perhaps fixing it's problems.
I wonder how someone can create the package with having chown DEBIAN to root.
Perhaps do you compile as root (which I wouldn't recommend).
Hopefully this works for everyone on linux debian.