Only include deb files and Packages in packages.tgz

- Previously, we included the entire contents of $PRODUCT_OUT/packages
in the tarball that we deploy to the rootfs. Change this to only include
.deb files and the Packages file, which contains the repository
- Saves several hundred megabytes on the rootfs of a development build
on Excelsior.

Change-Id: I14a01e168e1b6e00892df6dc29e635337f318722
1 file changed