Actually remove dependency on droid-system-packager

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
Don't depend on droid-hal-device when installing devel.
This is more of a -headers -debuginfo package compared to a normal -devel which typically requires access to the libraries provided in the main package.

Signed-off-by: David Greaves <david.greaves@jollamobile.com>
Store hw-release as /usr/lib/droid-devel/hw-release.vars for use at build time

Signed-off-by: David Greaves <david.greaves@jollamobile.com>